Sample records for interactions symbiosis predator-prey

  1. Investigating Predator-Prey Interactions

    NSDL National Science Digital Library

    Ethel D. Stanley (Beloit College; Biology)

    2006-05-20

    In a mixed culture, how does the population of Didinium affect the population of Paramecium â?? and vice versa? Predator-prey cycles can be modeled using the Biota simulation. How do variables such as the presence of a refuge or the availability of food perturb the population cycles? * study the effects that the presence of a refuge from predators has on a model microbial population

  2. Predator prey interactions with time delays

    Microsoft Academic Search

    J. M. Cushing

    1976-01-01

    A general (Volterra-Lotka type) integrodifferential system which describes a predator-prey interaction subject to delay effects is considered. A rather complete picture is drawn of certain qualitative aspects of the solutions as they are functions of the parameters in the system. Namely, it is argued that such systems have, roughly speaking, the following features. If the carrying capacity of the prey

  3. Modelling Seasonal Predator-Prey Interactions

    Microsoft Academic Search

    Jeppe Sturis; Carsten Knudsen

    1996-01-01

    We analyse an existing two variable model of predator-prey interactions. The analysis reveals problems in the model formulation. The main problem is related to the fact that the model is a mixture of empirically and causally based dynamic equations. An attempt to repair the model is made, but a completely satisfactory solution is not reached. We argue that model constructions,

  4. Predator-Prey Interactions of Marine Invaders

    Microsoft Academic Search

    Gil Rilov

    Predator-prey interactions are among the most fundamental processes shaping the structure and function of ecological communities,\\u000a particularly in marine systems. In the past several decades, it has become clear that humans are interfering considerably\\u000a with these interactions in many marine systems, mainly by removing top predators via harvesting (Myers and Worm 2003), but\\u000a also through biological introductions. Most introduced species

  5. A nonlocal kinetic model for predator-prey interactions R. C. Fetecau

    E-print Network

    Fetecau, Razvan C.

    A nonlocal kinetic model for predator-prey interactions R. C. Fetecau J. Meskas April 28, 2013 and by including a second species. The two species, assumed to have a predator-prey relationship, have dynamics as predator-prey relationships. We illustrate numerically a diverse set of predator-prey behaviours that can

  6. Global stability of predator-prey interactions

    Microsoft Academic Search

    Gary W. Harrison

    1979-01-01

    A Lyapunov function is given that extends functions used by Volterra, Goh, and Hsu to a wide class of predator-prey models, including Leslie type models, and a biological interpretation of this function is given. It yields a simple stability criterion, which is used to examine the effect on stability of intraspecific competition among both prey and predators, of a refuge

  7. Putting predators back into behavioral predator–prey interactions

    Microsoft Academic Search

    Steven L. Lima

    2002-01-01

    In the study of behavioral predator–prey interactions, predators have been treated as abstract sources of risk to which prey respond, rather than participants in a larger behavioral interaction. When predators are put back into the picture by allowing them to respond strategically to prey behavior, expectations about prey behavior can change. Something as simple as allowing predators to move in

  8. Effects of an Infectious Fungus, Batrachochytrium dendrobatidis, on Amphibian Predator-Prey Interactions

    E-print Network

    Blaustein, Andrew R.

    , on Amphibian Predator-Prey Interactions. PLoS ONE 6(2): e16675. doi:10.1371/journal.pone.0016675 Editor: Howard-predatory behaviors with important consequences for predator-prey interactions. For example, several studies revealEffects of an Infectious Fungus, Batrachochytrium dendrobatidis, on Amphibian Predator-Prey

  9. Bacterial Predator-Prey Interaction atLowPreyDensity

    Microsoft Academic Search

    M. VARON; ANDB. P. ZEIGLER

    1978-01-01

    A bacterial predator-prey interaction wasstudied using Bdellovibrio andbio- luminescent preybacteria. Theattacking bdeliovibrio causes decayofbiolumi- nescence, whichiscorrelated withbdellovibrio penetration intotheprey. The behavior ofthepreyandpredator populations overtimewasfoundtobewell described byaLotka-Volterra model. Byusing this model, theprobability of bdellovibrio penetration after encountering apreycell wasfound tobeapproxi- mately 3.0%. Thepreydensity required togivethebdellovibrios a50%chance of survival wascalculated tobeatleast 3.0x 106cells perml,andthedensity required forpopulation equilibria wascalculated tobeabout 7x105preybacteria perml.Thesevalues, notgenerally

  10. Modulation of predator–prey interactions by the Allee effect

    Microsoft Academic Search

    Ariane Verdy

    2010-01-01

    An Allee effect arising from density-dependent mating success can have significant impacts at the ecosystem level when considered in the context of predator–prey interactions. These are captured by a mathematical model for the exchange of biomass between a structured predator population (continuous weight distribution) and a resource. Because the predator’s mating success affects the amount of resources required for the

  11. Mean free-path length theory of predator–prey interactions: Application to juvenile salmon migration

    Microsoft Academic Search

    James J. Anderson; Eliezer Gurarie; Richard W. Zabel

    2005-01-01

    Ecological theory traditionally describes predator–prey interactions in terms of a law of mass action in which the prey mortality rate depends on the density of predators and prey. This simplifying assumption makes population-based models more tractable but ignores potentially important behaviors that characterize predator–prey dynamics. Here, we expand traditional predator–prey models by incorporating directed and random movements of both predators

  12. Three-dimensional predator-prey interactions: a computer simulqtion of bird flocks and aircraft

    E-print Network

    Dill, Lawrence M.

    Three-dimensional predator-prey interactions: a computer simulqtion of bird flocks and aircraft-dimensional predator-prey interactions: a computer simulation of bird flocks and aircraft. Can. J. Zool. 64: 2624-2633. Three-dimensional interactions between grouped aerial predators (frontal discs of aircraft engines

  13. Habitat-Mediated Predator-Prey Interactions in the Eastern Gulf of Primary Investigator: Doran Mason -NOAA /GLERL

    E-print Network

    Habitat-Mediated Predator-Prey Interactions in the Eastern Gulf of Mexico Primary Investigator-mediated predator-prey interactions and predator growth rate where H is non-consumable habitat (patch reef size as a function of habitat NPRED = NPRED(H). (C) Predator-prey interactions, resulting in predator consumption

  14. Role reversal in a predator-prey interaction.

    PubMed

    Sánchez-Garduño, Faustino; Miramontes, Pedro; Marquez-Lago, Tatiana T

    2014-10-01

    Predator-prey relationships are one of the most studied interactions in population ecology. However, little attention has been paid to the possibility of role exchange between species, despite firm field evidence of such phenomena in nature. In this paper, we build a mathematical model capable of reproducing the main phenomenological features of role reversal in a classical system and present results for both the temporal and spatio-temporal cases. We show that, depending on the choice of parameters, our role-reversal dynamical system exhibits excitable-like behaviour, generating waves of species' concentrations that propagate through space. Our findings fill a long-standing gap in modelling ecological interactions and can be applicable to better understanding ecological niche shifts and planning of sustainable ecosystems. PMID:26064541

  15. Role reversal in a predator–prey interaction

    PubMed Central

    Sánchez-Garduño, Faustino; Miramontes, Pedro; Marquez-Lago, Tatiana T

    2014-01-01

    Predator–prey relationships are one of the most studied interactions in population ecology. However, little attention has been paid to the possibility of role exchange between species, despite firm field evidence of such phenomena in nature. In this paper, we build a mathematical model capable of reproducing the main phenomenological features of role reversal in a classical system and present results for both the temporal and spatio-temporal cases. We show that, depending on the choice of parameters, our role-reversal dynamical system exhibits excitable-like behaviour, generating waves of species' concentrations that propagate through space. Our findings fill a long-standing gap in modelling ecological interactions and can be applicable to better understanding ecological niche shifts and planning of sustainable ecosystems.

  16. Long-range interactions and evolutionary stability in a predator-prey system Erik M. Rauch1,2

    E-print Network

    Long-range interactions and evolutionary stability in a predator-prey system Erik M. Rauch1 be responsible for long-term stability of predator-prey systems. Complete mixing results in rapid global extinctions. We consider the robustness of a generic evolving predator- prey or host-pathogen model to long

  17. A synthesis of subdisciplines: predator–prey interactions and biodiversity and ecosystem functioning

    Microsoft Academic Search

    Anthony R. Ives; J Bradley; E William; Marine Biology

    Abstract The last 15 years has seen parallel surges of interest in two research areas that have rarely intersected: biodiversity and ecosystem functioning (BEF), and multispecies predator– prey,interactions (PPI). Research addressing,role of,biodiversity in ecosystem functioning has focused primarily on single trophic-level systems, emphasizing additive effects of diversity that manifest through resource partitioning and the sampling effect. Conversely, research addressing predator–prey

  18. Enhancing species distribution modeling by characterizing predator-prey interactions.

    PubMed

    Trainor, Anne M; Schmitz, Oswald J; Ivan, Jacob S; Shenk, Tanya M

    2014-01-01

    Niche theory is a well-established concept integrating a diverse array of environmental variables and multispecies interactions used to describe species geographic distribution. It is now customary to employ species distribution models (SDMs) that use environmental variables in conjunction with species location information to characterize species' niches and map their geographic ranges. The challenge remains, however, to account for the biotic interactions of species with other community members on which they depend. We show here how to connect species spatial distribution and their dependence with other species by modeling spatially explicit predator-prey interactions, which we call a trophic interaction distribution model (TIDM). To develop the principles, we capitalized on data from Canada lynx (Lynx canadensis) reintroduced into Colorado. Spatial location information for lynx obtained from telemetry was used in conjunction with environmental data to construct an SDM. The spatial locations of lynx-snowshoe hare encounters obtained from snow-tracking in conjunction with environmental data were used to construct a TIDM. The environmental conditions associated with lynx locations and lynx-hare encounters identified through both SDM and TIDM revealed an initial transient phase in habitat use that settled into a steady state. Nevertheless, despite the potential for the SDM to broadly encompass all lynx hunting and nonhunting spatial locations, the spatial extents of the SDM and TIDM differed; about 40% of important lynx-snowshoe hare locations identified in the TIDM were not identified in the lynx-only SDM. Our results encourage greater effort to quantify spatial locations of trophic interactions among species in a community and the associated environmental conditions when attempting to construct models aimed at projecting current and future species geographic distributions. PMID:24640545

  19. Predator-prey Interactions with Delays Due to Juvenile Maturation

    Microsoft Academic Search

    Kenneth L. Cooke; Richard H. Elderkin; Wenzhang Huang

    2006-01-01

    This paper focuses on predator-prey models with juvenile\\/mature class structure for each of the predator and prey populations in turn, further classified by whether juvenile or mature individuals are active with respect to the predation process. These models include quite general prey recruitment at every stage of analysis, with mass action predation, linear predator mortality as well as delays in

  20. Probabilistic transition from unstable predator-prey interaction to stable coexistence of Dictyostelium discoideum and Escherichia coli

    Microsoft Academic Search

    Kumiko Kihara; Kotaro Mori; Shingo Suzuki; Kazufumi Hosoda; Akito Yamada; Shin-Ichi Matsuyama; Akiko Kashiwagi; Tetsuya Yomo

    2011-01-01

    Predator–prey interactions have been found at all levels within ecosystems. Despite their ecological ubiquity and importance, the process of transition to a stable coexistent state has been poorly verified experimentally. To investigate the stabilization process of predator–prey interactions, we previously constructed a reproducible experimental predator–prey system between Dictyostelium discoideum and Escherichia coli, and showed that the phenotypically changed E. coli

  1. System behaviour in predator-prey interaction, with special reference to acarine predator-prey system

    Microsoft Academic Search

    Akio Takafuji; Yoshio Tsuda; Toshihiro Miki

    1983-01-01

    Summary  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Laboratory experiments on the interaction between phytophagous tetranychid mites and predacious phytoseiid mites in multi-patch\\u000a systems showed that it was difficult to obtain a continued interaction between them when prey heavily over-exploit their host\\u000a plants. The experiments suggested that the stability conditions concluded from theMaynard Smith model which assumed a stable relationship between prey and resource would be

  2. Half-soliton interaction of population taxis waves in predator-prey systems with pursuit and M. A. Tsyganov

    E-print Network

    Biktashev, Vadim N.

    Half-soliton interaction of population taxis waves in predator-prey systems with pursuit type of interaction of waves in a mathe- matical model of "prey-predator" system with taxis, a "half populations in a "predator-prey" relationship with each other, started in our previous works [1

  3. Quasi-soliton interaction of pursuit-evasion waves in a predator-prey system M. A. Tsyganov

    E-print Network

    Biktashev, Vadim N.

    Quasi-soliton interaction of pursuit-evasion waves in a predator-prey system M. A. Tsyganov differential equations describing two spatially distributed populations in a "predator-prey" interaction the gradient of prey (pursuit), negative taxis of prey down the gradient of predators (evasion) and diffusion

  4. Predator-prey interactions of salmon in the plume and near-shore ocean

    E-print Network

    Predator-prey interactions of salmon in the plume and near-shore ocean: implications for density), Elizabeth Daly, Jim Ruzicka (OSU), and Beth Phillips (UW) CRBF & W Ocean Workshop, February 14, 2013 #12;Presentation Outline · Background on competition involving salmon in the ocean · Interactions between wild

  5. Analysis of a spatial Lotka-Volterra model with a finite range predator-prey interaction

    E-print Network

    Brigatti, E; Oliva, M; 10.1140/epjb/e2011-10826-6

    2012-01-01

    We perform an analysis of a recent spatial version of the classical Lotka-Volterra model, where a finite scale controls individuals' interaction. We study the behavior of the predator-prey dynamics in physical spaces higher than one, showing how spatial patterns can emerge for some values of the interaction range and of the diffusion parameter.

  6. Predator–prey interactions paradigm: a new tool for artificial intelligence

    Microsoft Academic Search

    Pierre Legreneur; Michel Laurin; Vincent Bels

    2012-01-01

    Predator–prey interactions are probably one of the key mechanisms for explaining the evolution of organisms in their ecosystems. Scientific fields relevant to understanding the mechanisms of these interactions are as diverse as evolutionary biology, behavioral ecology, ecomorphology, molecular biology, phylogeny, neurosciences, physiology, biomechanics, and robotics. The difficulty in understanding these mechanisms lies therefore (1) in the multi- and interdisciplinary nature

  7. Predator–prey interactions of Procambarus clarkii with aquatic macroinvertebrates in single and multiple prey systems

    Microsoft Academic Search

    Alexandra Marçal Correia; Nuno Bandeira; Pedro Manuel Anastácio

    2005-01-01

    Understanding the interspecific interactions of Procambarus clarkii with other aquatic macroinvertebrates will help to unveil the mechanisms and processes underlying biological invasiveness. The purpose of this study was to investigate predator–prey interactions of two ontogenic phases of P. clarkii with native and exotic species of aquatic macroinvertebrates at a single and multiple prey level. We performed laboratory experiments to determine

  8. Coexistence in reaction-diffusion systems with mutualist or predator-prey interactions

    Microsoft Academic Search

    Walter Kelley

    1996-01-01

    The question of the coexistence of two species that exhibit mutualist or predator-prey interactions and satisfy a reaction-diffusion system is studied. It is shown in both cases that under favorable conditions initial populations that are limited in space will never fall below known positive population densities and will eventually extend throughout the potential region of cohabitation. We consider below the

  9. Availability of prey resources drives evolution of predator–prey interaction

    Microsoft Academic Search

    Ville-Petri Friman; Teppo Hiltunen; Jouni Laakso; Veijo Kaitala

    2008-01-01

    Productivity is predicted to drive the ecological and evolutionary dynamics of predator-prey interaction through changes in resource allocation between different traits. Here we report results of an evolutionary experiment where prey bacteria Serratia marcescens was exposed to predatory protozoa Tetrahymena thermophila in low- and high-resource environments for approximately 2400 prey generations. Predation generally increased prey allocation to defence and caused

  10. Evolution of predator-prey interactions in ancient lakes: implications for coevolution in marine environments

    Microsoft Academic Search

    1985-01-01

    Highly generalized predator-prey interrelationships are a hallmark of most lacustrine ecosystems where accommodation to the physical environment plays the major role in determining organismal distributions. Since the vast majority of lakes are ephemeral on a geological and evolutionary times scale, dispersal, rather than organism interaction, appears to be the dominant selective theme in lacustrine species evolution. In a few, very

  11. A synthesis of subdisciplines: predator-prey interactions, and biodiversity and ecosystem functioning

    Microsoft Academic Search

    Anthony R. Ives; Bradley J. Cardinale

    The last 15 years has seen parallel surges of interest in two research areas that have rarely intersected: biodiversity and ecosystem functioning (BEF), and multispecies predator- prey interactions (PPI). Research addressing role of biodiversity in ecosystem functioning has focused primarily on single trophic-level systems, emphasizing additive effects of diversity that manifest through resource partitioning and the sampling effect. Conversely, research

  12. The influence of initial age structure on predator–prey interaction

    Microsoft Academic Search

    Th. Hance; G. Van Impe

    1999-01-01

    Initial age structure influences the growth of a prey population and the outcome of the predator–prey interaction. In order to quantify that influence, we employed a simple numerical model using experimental data from the system Tetranychus urticae–Phytoseiulus persimilis. Four major points were drawn from the results: (1) A population created by young females grows much faster than a population created

  13. Predator-prey interaction coupled by parasitic infection: Limit cycles and chaotic behavior

    Microsoft Academic Search

    Y. Lenbury; S. Rattanamongkonkul; N. Tumrasvin; S. Amornsamankul

    1999-01-01

    Several extensive studies have been carried out to document the ability of parasites to alter the behavior of infected hosts [13?]. In this paper, we discuss the population dynamic consequences of parasite-induced changes in the behavior of the two interacting species in a predator-prey system, by means of the development and analysis of mathematical models. First, in order to investigate

  14. Enrichment and foodchain stability: the impact of different forms of predator–prey interaction

    Microsoft Academic Search

    Thilo Gross; Wolfgang Ebenhöh; Ulrike Feudel

    2004-01-01

    We propose a simple model of an ecological foodchain of arbitrary length. The model is very general in nature and describes a whole class of foodchains. Using the methods of qualitative analysis the model's stability can be analysed without restricting the predator–prey interaction to any specific functional form. The model can therefore be used to study the effect of different

  15. Episodic disturbance events modify predator–prey interactions in soft sediments

    Microsoft Academic Search

    S. P. Eriksson; H. Wennhage; J. Norkko; A. Norkko

    2005-01-01

    Physical disturbance events are common in shallow soft-sediment habitats and can have significant effects on predator–prey interactions. While several studies have reported on predator aggregations following disturbance events, few studies have investigated the mechanisms and interactive effects of predation and physical disturbance on prey survival in shallow soft-sediment habitats. In this study the interactive effects of sediment resuspension and predation

  16. Predator-prey interactions in size-structured fish communities: implications of prey growth

    Microsoft Academic Search

    Mark H. Olson

    1996-01-01

    Predator-prey interactions among size-structured populations may be strongly influenced by factors which affect growth rates of prey. I examined the importance of prey growth in the interaction between large-mouth bass (Micropterus salmoides) and their prey, bluegill (Lepomis macrochirus), by analyzing diets and growth rates of bass in a set of seven lakes in south-central Wisconsin. Sizes of bluegill consumed by

  17. Increased nitrogen availability influences predator–prey interactions by altering host-plant quality

    Microsoft Academic Search

    John J. Couture; Jason S. Servi; Richard L. Lindroth

    2010-01-01

    Little is known about how plant nutritional and defensive qualities interact to influence predator–prey interactions. To address\\u000a this need, we provided the neo-tropical milkweed, Asclepias curassavica, with two levels of nitrogen availability and examined how altered host-plant quality influenced the responses of a specialist\\u000a aphid, Aphis nerii, and a coccinellid predator, Harmonia axyridis. Aphis nerii uses A. curassavica for multiple

  18. PREDATOR-PREY INTERACTIONS AND FUNCTIONAL DESIGN: PHENOTYPIC PLASTICITY IN SUNFISHES AND THE DEVELOPMENT OF GENERAL FORAGING MODELS

    Microsoft Academic Search

    Craig W. Osenberg; Casey J Fisher Huckins

    Predator-prey interactions are influenced by a myriad of factors (e.g., encounter rate, capture success, handling efficiency, predator avoidance, etc.), which are ultimately determined by the phenotype of the predator (e.g., gape size, muscle mass, feeding behavior) and the prey (e.g., body size, shell hardness). Thus, the development of general models of predator-prey interactions requires approaches that simultaneously incorporate mechanisms that

  19. Effect of Mirex on Predator-Prey Interaction in an Experimental Estuarine Ecosystem

    Microsoft Academic Search

    Marlin E. Tagatz

    1976-01-01

    Tests of 14- to 16-days duration were conducted to determine the distribution and sublethal effects of mirex in an experimental estuarine ecosystem. The insecticide was translocated from water at concentrations of 0.011 to 0.13 ?g\\/liter to sand, plant, and animal components. An alteration of predator-prey interaction due to mirex was manifested by a significant difference (X test, ? = 0.05)

  20. Water turbidity affects predator–prey interactions in a fish–damselfly system

    Microsoft Academic Search

    Frank Van de Meutter; Luc De Meester; Robby Stoks

    2005-01-01

    Community structure may differ dramatically between clear-water and turbid lakes. These differences have been attributed to\\u000a differences in the cascading effect of fish on prey populations, owing to the reduced efficiency of fish predation in the\\u000a presence of macrophytes. However, recent theoretical ideas suggest that water turbidity may shape predator–prey interactions,\\u000a and it is predicted that prey will relax its

  1. Positive solutions for ratio-dependent predator–prey interaction systems

    Microsoft Academic Search

    Kimun Ryu; Inkyung Ahn

    2005-01-01

    In this paper, we study the dynamics of predator–prey interaction systems between two species with ratio-dependent functional responses. First we provide sufficient and necessary conditions for positive steady-state solutions, and then we investigate the relationships between positive equilibria and positive solutions of the system over a large domain. Furthermore, we deal with the uniqueness and the stability of positive steady-states

  2. Predator-Prey Interaction between Largemouth Bass and Bluegills as Influenced by Simulated, Submersed Vegetation

    Microsoft Academic Search

    Jacqueline F. Savino; Roy A. Stein

    1982-01-01

    Data from the literature suggest that predatory success declines as habitat complexity increases. To explain this phenomenon, we studied the predator-prey interaction between largemouth bass Micropterus salmoides and bluegills Lepomis macrochirus in four laboratory pools (2.4–3.0 m diameter, 0.7 m deep), each with a different density (0, 50, 250, 1,000 stems\\/m) of artificial plant stems. Behavior was quantified for both

  3. The role of turbidity as a constraint on predator-prey interactions in aquatic environments

    Microsoft Academic Search

    Mark V. Abrahams; Michael G. Kattenfeld

    1997-01-01

    Many of the world's most productive aquatic ecosystems usually contain turbid water. Paradoxically, many fish species that\\u000a live in these habitats are also those that often rely on vision to detect their predators and their prey. For these fish,\\u000a turbidity will reduce the distance at which predator-prey interactions occur, and there should be a reduction in the opportunity\\u000a for behavioural

  4. Predator-Prey Interactions of Fishes under the Influence of Ammonia

    Microsoft Academic Search

    D. M. Woltering; J. L. Hedtke; L. J. Weber

    1978-01-01

    Food consumption and growth rates of a predator, the largemouth bass (Micropterus salmoides), and the behavior of both the predator and its prey, the mosquitofish (Gambusia affinis), were sensitive indices of sublethal effects of ammonia on predator-prey interactions. Prey consumption and growth rates of bass in control tests increased with increasing prey densities. Ammonia concentrations of 0.63 and 0.86 mg\\/liter

  5. Waves affect predator–prey interactions between fish and benthic invertebrates

    Microsoft Academic Search

    Friederike Gabel; Stefan Stoll; Philipp Fischer; Martin T. Pusch; Xavier-François Garcia

    2011-01-01

    Little is known about the effects of waves on predator–prey interactions in the littoral zones of freshwaters. We conducted\\u000a a set of mesocosm experiments to study the differential effects of ship- and wind-induced waves on the foraging success of\\u000a littoral fish on benthic invertebrates. Experiments were conducted in a wave tank with amphipods (Gammarus roeseli) as prey, and age-0 bream

  6. Predator-prey interactions between two amphibian species: effects of insecticide exposure

    Microsoft Academic Search

    Christine M. Bridges

    1999-01-01

    The presence of environmental contaminants may alter predator-prey interactions among aquatic species by altering activity\\u000a levels of predators or prey, or by altering predator avoidance behavior. The outcome of a predatory encounter may be dependent\\u000a upon whether both species are exposed to a contaminant simultaneously, or whether exposure occurs only in one of the species.\\u000a In a laboratory experiment, I

  7. Random predator-prey interactions in a varying environment: Extinction or survival

    Microsoft Academic Search

    S. S. De

    1984-01-01

    The random predator-prey type interactions of the population species in a random varying environment have been investigated.\\u000a The Fokker-Planck equation for the transition probability, corresponding to the stochastic differential equations established\\u000a from Lotka-Volterra equations by the introduction of randomness and variability, has been integrated in the form of a path\\u000a integral. The transition probabilities for extinction or survival of one

  8. Spatial Variability Enhances Species Fitness in Stochastic Predator-Prey Interactions

    Microsoft Academic Search

    Ulrich Dobramysl; Uwe C. Täuber

    2008-01-01

    We study the influence of spatially varying reaction rates on a spatial stochastic two-species Lotka-Volterra lattice model for predator-prey interactions using two-dimensional Monte Carlo simulations. The effects of this quenched randomness on population densities, transient oscillations, spatial correlations, and invasion fronts are investigated. We find that spatial variability in the predation rate results in more localized activity patches, which in

  9. Fluctuations and correlations in lattice models for predator-prey interaction

    Microsoft Academic Search

    Mauro Mobilia; Ivan T. Georgiev; Uwe C. Täuber

    2006-01-01

    Including spatial structure and stochastic noise invalidates the classical Lotka-Volterra picture of stable regular population cycles emerging in models for predator-prey interactions. Growth-limiting terms for the prey induce a continuous extinction threshold for the predator population whose critical properties are in the directed percolation universality class. We discuss the robustness of this scenario by considering an ecologically inspired stochastic lattice

  10. A predator–prey interaction model with self and cross-diffusion

    Microsoft Academic Search

    B. Dubey; B. Das; J. Hussain

    2001-01-01

    In this paper, a mathematical model for a predator–prey interaction with self and cross-diffusion is proposed and analysed. Criteria for local stability, instability and global stability are obtained. The effect of the critical wave length which can drive a system to instability is investigated. The effect of time-varying cross-diffusivity on the stability of the system is also examined.

  11. Simple predator–prey interactions control dynamics in a plankton food web model

    Microsoft Academic Search

    Roger Cropp; John Norbury

    2009-01-01

    A plankton food web model is analysed using interaction parameter values appropriate to the upper mixed layer of the high latitude oceans. The dynamics of this four-variable system are analysed in terms of the dynamics of much simpler two-variable predator–prey subsystems. Thus, the food web's robust, periodic, four-dimensional dynamics are explained by means of two-dimensional spirals and limit cycles. These

  12. Predator-prey interactions: is 'ecological stoichiometry' sufficient when good food goes bad?

    Microsoft Academic Search

    Aditee Mitra; Kevin J Flynn

    2005-01-01

    The dietary value of a prey type varies with its nutritional status and hence with its C:N:P content. However, while stoichiometric differences between a heterotroph and its food must affect growth efficiency (GE), and thence trophic dynamics, other factors related to food quality may act as powerful modulators of predator-prey interactions. Thus, minor changes in prey stoichiometry can be associated

  13. Simulations of the predator-prey interactions in a two species ecotoxicological test system

    Microsoft Academic Search

    Jørgen Aagaard Axelsen; Niels Holst; Timo Hamers; Paul Henning Krogh

    1997-01-01

    A mathematical simulation model (Gutierrez type) has been developed to investigate the predator-prey interactions in a two species ecotoxicological test system. The test system consists of the predacious mite (Hypoaspis aculeifer Canestrini) and, as prey, the collembolan Folsomia fimetaria L. in a microcosm (5.5 cm high × 6.0 cm in diameter) with 30 g humidified soil. F. fimetaria is provided

  14. Predator-prey interactions between shell-boring beetle larvae and rock-dwelling land snails.

    PubMed

    Baalbergen, Els; Helwerda, Renate; Schelfhorst, Rense; Castillo Cajas, Ruth F; van Moorsel, Coline H M; Kundrata, Robin; Welter-Schultes, Francisco W; Giokas, Sinos; Schilthuizen, Menno

    2014-01-01

    Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies. PMID:24964101

  15. Predator-Prey Interactions between Shell-Boring Beetle Larvae and Rock-Dwelling Land Snails

    PubMed Central

    Castillo Cajas, Ruth F.; van Moorsel, Coline H. M.; Kundrata, Robin; Welter-Schultes, Francisco W.; Giokas, Sinos; Schilthuizen, Menno

    2014-01-01

    Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies. PMID:24964101

  16. Evolution of predator-prey interactions in ancient lakes: implications for coevolution in marine environments

    SciTech Connect

    Cohen, A.

    1985-01-01

    Highly generalized predator-prey interrelationships are a hallmark of most lacustrine ecosystems where accommodation to the physical environment plays the major role in determining organismal distributions. Since the vast majority of lakes are ephemeral on a geological and evolutionary times scale, dispersal, rather than organism interaction, appears to be the dominant selective theme in lacustrine species evolution. In a few, very long lasting lakes, notably modern Lakes Tanganyika (Africa) and Baikal (USSR) and ancient lakes of the Brazilian Rift (Cretaceous) and Snake River Plain (Tertiary), invertebrates and fish occur which demonstrate the development of intense biological accommodation in coevolving predator-prey interactions. Shell crushing experiments on 2 endemic Tanganyikan gastropods, Lavigeria nassa and Spekia zonata show them to be comparable to warm temperature marine species in terms of grow load strength: 1-2 orders of magnitude stronger than confamilial cosmopolitan species from more ephemeral lakes in the same region of Africa. Shell repair is commonly observed in these and other Tanganyikan endemic snails although it is exceedingly rare inmost other lakes. The study of these early stages of evolutionary processes and rates in coevolving predator-prey systems in isolated lacustrine microcosms has important implications for those paleontologists concerned with marine invertebrates. It may shed considerable light on the interpretation of such events as the marine Mesozoic Revolution.

  17. Spatial ecology of predator-prey interactions:; corridors and patch shape influence seed predation

    Microsoft Academic Search

    John L. Orrock; Brent J. Danielson; Molly J. Burns; Douglas J. Levey

    2003-01-01

    J.L. Orrock, B.J. Danielson, M.J. Burns, and D.J. Levey. 2003. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation.;\\u000a Ecology, 84(10):2589-2599.;\\u000a;\\u000aAbstract: Corridors that connect patches of disjunct habitat may be promising tools;\\u000afor mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes,

  18. Chytridiomycosis impacts predator-prey interactions in larval amphibian communities

    Microsoft Academic Search

    Matthew J. Parris; Joseph G. Beaudoin

    2004-01-01

    Despite ecologists increasingly recognizing pathogens as playing significant roles in community dynamics, few experimental studies have quantified patterns of disease impacts on natural systems. Amphibians are experiencing population declines, and a fungal pathogen ( Batrachochytrium dendrobatidis; Chytridiomycota) is a suspected causal agent in many declines. We studied the effects of a pathogenic fungus on community interactions between the gray treefrog,

  19. Fluctuations and correlations in lattice models for predator-prey interaction

    Microsoft Academic Search

    Mauro Mobilia; Ivan T. Georgiev; Uwe C. Tauber

    2006-01-01

    Including spatial structure and stochastic noise invalidates the classical\\u000aLotka-Volterra picture of stable regular population cycles emerging in models\\u000afor predator-prey interactions. Growth-limiting terms for the prey induce a\\u000acontinuous extinction threshold for the predator population whose critical\\u000aproperties are in the directed percolation universality class. Here, we discuss\\u000athe robustness of this scenario by considering an ecologically inspired\\u000astochastic

  20. Genetic variation, predator–prey interactions and food web structure

    PubMed Central

    Moya-Laraño, Jordi

    2011-01-01

    Food webs are networks of species that feed on each other. The role that within-population phenotypic and genetic variation plays in food web structure is largely unknown. Here, I show via simulation how variation in two key traits, growth rates and phenology, by influencing the variability of body sizes present through time, can potentially affect several structural parameters in the direction of enhancing food web persistence: increased connectance, decreased interaction strengths, increased variation among interaction strengths and increased degree of omnivory. I discuss other relevant traits whose variation could affect the structure of food webs, such as morphological and additional life-history traits, as well as animal personalities. Furthermore, trait variation could also contribute to the stability of food web modules through metacommunity dynamics. I propose future research to help establish a link between within-population variation and food web structure. If appropriately established, such a link could have important consequences for biological conservation, as it would imply that preserving (functional) genetic variation within populations could ensure the preservation of entire communities. PMID:21444316

  1. Reciprocal Behavioral Plasticity and Behavioral Types during Predator-Prey Interactions

    PubMed Central

    McGhee, Katie E.; Pintor, Lauren M.; Bell, Alison M.

    2014-01-01

    How predators and prey interact has important consequences for population dynamics and community stability. Here we explored how predator-prey interactions are simultaneously affected by reciprocal behavioral plasticity (i.e., plasticity in prey defenses countered by plasticity in predator offenses and vice versa) and consistent individual behavioral variation (i.e., behavioral types) within both predator and prey populations. We assessed the behavior of a predator species (northern pike) and a prey species (three-spined stickleback) during one-on-one encounters. We also measured additional behavioral and morphological traits in each species. Using structural equation modeling, we found that reciprocal behavioral plasticity as well as predator and prey behavioral types influenced how individuals behaved during an interaction. Thus, the progression and ultimate outcome of predator-prey interactions depend on both the dynamic behavioral feedback occurring during the encounter and the underlying behavioral type of each participant. We also examined whether predator behavioral type is underlain by differences in metabolism and organ size. We provide some of the first evidence that behavioral type is related to resting metabolic rate and size of a sensory organ (the eyes). Understanding the extent to which reciprocal behavioral plasticity and intraspecific behavioral variation influence the outcome of species interactions could provide insight into the maintenance of behavioral variation as well as community dynamics. PMID:24231533

  2. Reciprocal behavioral plasticity and behavioral types during predator-prey interactions.

    PubMed

    McGhee, Katie E; Pintor, Lauren M; Bell, Alison M

    2013-12-01

    How predators and prey interact has important consequences for population dynamics and community stability. Here we explored how predator-prey interactions are simultaneously affected by reciprocal behavioral plasticity (i.e., plasticity in prey defenses countered by plasticity in predator offenses and vice versa) and consistent individual behavioral variation (i.e., behavioral types) within both predator and prey populations. We assessed the behavior of a predator species (northern pike) and a prey species (three-spined stickleback) during one-on-one encounters. We also measured additional behavioral and morphological traits in each species. Using structural equation modeling, we found that reciprocal behavioral plasticity as well as predator and prey behavioral types influenced how individuals behaved during an interaction. Thus, the progression and ultimate outcome of predator-prey interactions depend on both the dynamic behavioral feedback occurring during the encounter and the underlying behavioral type of each participant. We also examined whether predator behavioral type is underlain by differences in metabolism and organ size. We provide some of the first evidence that behavioral type is related to resting metabolic rate and size of a sensory organ (the eyes). Understanding the extent to which reciprocal behavioral plasticity and intraspecific behavioral variation influence the outcome of species interactions could provide insight into the maintenance of behavioral variation as well as community dynamics. PMID:24231533

  3. Acoustic mimicry in a predator–prey interaction

    PubMed Central

    Barber, Jesse R.; Conner, William E.

    2007-01-01

    Mimicry of visual warning signals is one of the keystone concepts in evolutionary biology and has received substantial research attention. By comparison, acoustic mimicry has never been rigorously tested. Visualizing bat–moth interactions with high-speed, infrared videography, we provide empirical evidence for acoustic mimicry in the ultrasonic warning sounds that tiger moths produce in response to echolocating bats. Two species of sound-producing tiger moths were offered successively to naïve, free-flying red and big brown bats. Noctuid and pyralid moth controls were also offered each night. All bats quickly learned to avoid the noxious tiger moths first offered to them, associating the warning sounds with bad taste. They then avoided the second sound-producing species regardless of whether it was chemically protected or not, verifying both Müllerian and Batesian mimicry in the acoustic modality. A subset of the red bats subsequently discovered the palatability of the Batesian mimic, demonstrating the powerful selective force these predators exert on mimetic resemblance. Given these results and the widespread presence of tiger moth species and other sound-producing insects that respond with ultrasonic clicks to bat attack, acoustic mimicry complexes are likely common components of the acoustic landscape. PMID:17517637

  4. Gyrokinetic turbulence cascade via predator-prey interactions between different scales

    NASA Astrophysics Data System (ADS)

    Kobayashi, Sumire; Gurcan, Ozgur D.

    2015-05-01

    Gyrokinetic simulations in a closed fieldline geometry are presented to explore the physics of nonlinear transfer in plasma turbulence. As spontaneously formed zonal flows and small-scale turbulence demonstrate "predator-prey" dynamics, a particular cascade spectrum emerges. The electrostatic potential and the density spectra appear to be in good agreement with the simple theoretical prediction based on Charney-Hasegawa-Mima equation |?˜ k | 2˜|n˜ k | 2?k-3/(1+k2 ) 2 , with the spectra becoming anisotropic at small scales. The results indicate that the disparate scale interactions, in particular, the refraction and shearing of larger scale eddies by the self-consistent zonal flows, dominate over local interactions, and contrary to the common wisdom, the comprehensive scaling relation is created even within the energy injection region.

  5. Sublethal effects and predator-prey interactions: implications for ecological risk assessment.

    PubMed

    Brooks, Amy C; Gaskell, Paul N; Maltby, Lorraine L

    2009-11-01

    Ecological risk assessments tend to focus on contaminant effects on single species in isolation. However, additional effects from interactions between species (e.g., predator-prey interactions) may also occur in natural systems. The present study investigated the consequences of sublethal contaminant effects in prey on predator-prey interactions, particularly the interaction between prey behavioral changes and predation by predators with different hunting strategies. Ambush (Ischnura elegans Vander Linden [Insecta, Odonata]) and active (Notonecta glauca Linnaeus [Insecta, Heteroptera]) predator species were used in conjunction with three prey species (Asellus aquaticus Linnaeus [Crustacea, Isopoda], Cloion dipterum Linnaeus [Insecta, Ephemeroptera], and Chironomus riparius Meigen [Insecta, Diptera]). Immobilized prey demonstrated the importance of prey behavior for determining predation rates for both single- and multiple-prey species. Chironomus riparius was less responsive following exposure to cadmium, becoming more vulnerableto attack by the active but not the ambush predator. Some evidence was also observed for reduced general activity in C. dipterum following cadmium exposure. Sublethal exposure of prey did not affect the prey choice of active predators, possibly because of prey behavioral changes being insufficient to influence their relative availabilities. However, cadmium exposure of prey did alter their susceptibility to ambush predators. There was a reduced proportion of C. dipterum and an increased proportion of A. aquaticus in the diet of ambush predators, possibly because of reduced activity in C. dipterum affecting their relative encounter rates with predators. Sublethal exposures can therefore result in reduced prey survival that would not be predicted by single-species toxicity tests. PMID:19572771

  6. Nonadditive impacts of temperature and basal resource availability on predator-prey interactions and phenotypes.

    PubMed

    Costa, Zacharia J; Kishida, Osamu

    2015-08-01

    Predicting the impacts of climate change on communities requires understanding how temperature affects predator-prey interactions under different biotic conditions. In cases of size-specific predation, environmental influences on the growth rate of one or both species can determine predation rates. For example, warming increases top-down control of food webs, although this depends on resource availability for prey, as increased resources may allow prey to reach a size refuge. Moreover, because the magnitude of inducible defenses depends on predation rates and resource availability for prey, temperature and resource levels also affect phenotypic plasticity. To examine these issues, we manipulated the presence/absence of predatory Hynobius retardatus salamander larvae and herbivorous Rana pirica tadpoles at two temperatures and three basal resource levels. and measured their morphology, behavior, growth and survival. Prior work has shown that both species express antagonistic plasticity against one another in which salamanders enlarge their gape width and tadpoles increase their body width to reach a size-refuge. We found that increased temperatures increased predation rates, although this was counteracted by high basal resource availability, which further decreased salamander growth. Surprisingly, salamanders caused tadpoles to grow larger and express more extreme defensive phenotypes as resource levels decreased under warming, most likely due to their increased risk of predation. Thus, temperature and resources influenced defensive phenotype expression and its impacts on predator and prey growth by affecting their interaction strength. Our results indicate that basal resource levels can modify the impacts of increased temperatures on predator-prey interactions and its consequences for food webs. PMID:25820751

  7. Suspended sediment alters predator-prey interactions between two coral reef fishes

    NASA Astrophysics Data System (ADS)

    Wenger, A. S.; McCormick, M. I.; McLeod, I. M.; Jones, G. P.

    2013-06-01

    Sediment derived from agriculture and development increases water turbidity and threatens the health of inshore coral reefs. In this study, we examined whether suspended sediment could change predation patterns through a reduction in visual cues. We measured survivorship of newly settled Chromis atripectoralis exposed to Pseudochromis fuscus, a common predator of juvenile damselfishes, in aquaria with one of four turbidity levels. Increased turbidity led to a nonlinear response in predation patterns. Predator-induced mortality was ~50 % in the control and low turbidity level, but exhibited a substantial increase in the medium level. In the highest turbidity level, predation rates declined to the level seen in the control. These results suggest an imbalance in how the predator and prey cope with turbidity. A turbidity-induced change to the outcome of predator-prey interactions represents a major change to the fundamental processes that regulate fish assemblages.

  8. Genetic Variation and Persistence of Predator-prey Interactions in the Nicholson–Bailey Model

    Microsoft Academic Search

    Michael Doebeli

    1997-01-01

    The unstable Nicholson–Bailey predator-prey model is extended by assuming that the predation efficiency depends on quantitative characters in both the prey and the predator. The genetics of these characters is assumed to be determined by many diploid loci with additive effects. It is shown that in contrast to the monomorphic model, predator-prey coexistence is possible in the genetically variable system,

  9. The effects of the functional response on the bifurcation behavior of a mite predator–prey interaction model

    Microsoft Academic Search

    John B. Collings

    1997-01-01

    .  ?A predator–prey interaction model based on a system of differential equations with temperature-dependent parameters chosen\\u000a appropriately for a mite interaction on apple trees is analyzed to determine how the type of functional response influences\\u000a bifurcation and stability behavior. Instances of type I, II, III, and IV functional responses are considered, the last of\\u000a which incorporates prey interference with predation. It

  10. Predicting the effects of ocean acidification on predator-prey interactions: a conceptual framework based on coastal molluscs.

    PubMed

    Kroeker, Kristy J; Sanford, Eric; Jellison, Brittany M; Gaylord, Brian

    2014-06-01

    The influence of environmental change on species interactions will affect population dynamics and community structure in the future, but our current understanding of the outcomes of species interactions in a high-CO2 world is limited. Here, we draw upon emerging experimental research examining the effects of ocean acidification on coastal molluscs to provide hypotheses of the potential impacts of high-CO2 on predator-prey interactions. Coastal molluscs, such as oysters, mussels, and snails, allocate energy among defenses, growth, and reproduction. Ocean acidification increases the energetic costs of physiological processes such as acid-base regulation and calcification. Impacted molluscs can display complex and divergent patterns of energy allocation to defenses and growth that may influence predator-prey interactions; these include changes in shell properties, body size, tissue mass, immune function, or reproductive output. Ocean acidification has also been shown to induce complex changes in chemoreception, behavior, and inducible defenses, including altered cue detection and predator avoidance behaviors. Each of these responses may ultimately alter the susceptibility of coastal molluscs to predation through effects on predator handling time, satiation, and search time. While many of these effects may manifest as increases in per capita predation rates on coastal molluscs, the ultimate outcome of predator-prey interactions will also depend on how ocean acidification affects the specified predators, which also exhibit complex responses to ocean acidification. Changes in predator-prey interactions could have profound and unexplored consequences for the population dynamics of coastal molluscs in a high-CO2 ocean. PMID:25070866

  11. Finite element approximation of spatially extended predator–prey interactions with the Holling type II functional response

    Microsoft Academic Search

    Marcus R. Garvie; Catalin Trenchea

    2007-01-01

    We study the numerical approximation of the solutions of a class of nonlinear reaction–diffusion systems modelling predator–prey\\u000a interactions, where the local growth of prey is logistic and the predator displays the Holling type II functional response.\\u000a The fully discrete scheme results from a finite element discretisation in space (with lumped mass) and a semi-implicit discretisation\\u000a in time. We establish a

  12. Phase portraits, Hopf bifurcations and limit cycles of the Holling–Tanner models for predator–prey interactions

    Microsoft Academic Search

    K. Q. Lan; C. R. Zhu

    2011-01-01

    The phase portraits, existence and uniqueness of stable limit cycles and Hopf bifurcations of the well-known Holling–Tanner models for predator–prey interactions are studied. The ranges of the parameters involved are provided under which the unique interior equilibrium can be determined to be a stable (or an unstable) node or focus. The Hopf bifurcations and the existence and uniqueness of stable

  13. Finite-Difference Schemes for Reaction–Diffusion Equations Modeling Predator–Prey Interactions in M ATLAB

    Microsoft Academic Search

    Marcus R. Garvie

    2007-01-01

    We present two finite-difference algorithms for studying the dynamics of spatially extended predator–prey interactions with\\u000a the Holling type II functional response and logistic growth of the prey. The algorithms are stable and convergent provided\\u000a the time step is below a (non-restrictive) critical value. This is advantageous as it is well-known that the dynamics of approximations\\u000a of differential equations (DEs) can

  14. Bifurcation and stability analysis of a temperature-dependent mite predator-prey interaction model incorporating a prey refuge

    Microsoft Academic Search

    John B. Collings; Grand Forks

    1995-01-01

    The non-linear behavior of a differential equations-based predator-prey model, incorporating a spatial refuge protecting a\\u000a consant proportion of prey and with temperature-dependent parameters chosen appropriately for a mite interaction on fruit\\u000a trees, is examined using the numerical bifurcation code AUTO 86. The most significant result of this analysis is the existence\\u000a of a temperature interval in which increasing the amount

  15. Effects of quenched randomness on predator-prey interactions in a stochastic Lotka-Volterra lattice model

    Microsoft Academic Search

    Uwe C. Tauber; Ulrich Dobramysl

    2008-01-01

    We study the influence of spatially varying reaction rates (i.e., quenched randomness) on a stochastic two-species Lotka-Volterra lattice model for predator-prey interactions using Monte Carlo simulations. The effects on the asymptotic population densities, transient oscillations, spatial distributions, and on traveling wave and invasion front speed velocities are investigated. We find that spatial variability in the predation rate yields an increase

  16. Infrared tomographic PIV and 3D motion tracking system applied to aquatic predator-prey interaction

    NASA Astrophysics Data System (ADS)

    Adhikari, Deepak; Longmire, Ellen K.

    2013-02-01

    Infrared tomographic PIV and 3D motion tracking are combined to measure evolving volumetric velocity fields and organism trajectories during aquatic predator-prey interactions. The technique was used to study zebrafish foraging on both non-evasive and evasive prey species. Measurement volumes of 22.5 mm × 10.5 mm × 12 mm were reconstructed from images captured on a set of four high-speed cameras. To obtain accurate fluid velocity vectors within each volume, fish were first masked out using an automated visual hull method. Fish and prey locations were identified independently from the same image sets and tracked separately within the measurement volume. Experiments demonstrated that fish were not influenced by the infrared laser illumination or the tracer particles. Results showed that the zebrafish used different strategies, suction and ram feeding, for successful capture of non-evasive and evasive prey, respectively. The two strategies yielded different variations in fluid velocity between the fish mouth and the prey. In general, the results suggest that the local flow field, the direction of prey locomotion with respect to the predator and the relative accelerations and speeds of the predator and prey may all be significant in determining predation success.

  17. Predator-Prey Simulation Exercises for the Classroom

    NSDL National Science Digital Library

    James Waddell (University of Maine at Orono; )

    2009-08-26

    Illustrations of predator-prey interactions looking at different prey distributions, structural complexity of the environment, prey's reproductive rate,and both predator-prey reproduction in a complex environment.

  18. PredatorPrey Relationships 933 PredatorPrey

    E-print Network

    are predators, but some are also preyed upon by other species. Theoretically, the interaction between marine interactions. I. Evolutionary Time Scales Predator­prey relationships have been likened to an evolutionary arms of the interactions between the predators and their prey (Taylor, 1984). As predators, marine mammals feed primarily

  19. REVISITING THE CLASSICS: CONSIDERING NONCONSUMPTIVE EFFECTS IN TEXTBOOK EXAMPLES OF PREDATOR–PREY INTERACTIONS

    Microsoft Academic Search

    Barbara L. Peckarsky; Peter A. Abrams; Daniel I. Bolnick; Lawrence M. Dill; Jonathan H. Grabowski; Barney Luttbeg; John L. Orrock; Scott D. Peacor; Evan L. Preisser; Oswald J. Schmitz; Geoffrey C. Trussell

    2008-01-01

    Predator effects on prey dynamics are conventionally studied by measuring changes in prey abundance attributed to consumption by predators. We revisit four classic examples of predator-prey systems often cited in textbooks and incorporate subsequent studies of nonconsumptive effects of predators (NCE), defined as changes in prey traits (e.g., behavior, growth, development) measured on an ecological time scale. Our review revealed

  20. Effect of pentachlorophenol on predator-prey interaction of two rotifers

    Microsoft Academic Search

    Africa Gómez; Gary Cecchine; Terry W Snell

    1997-01-01

    The effect of pentachlorophenol (PCP) on the predator-prey relationship of two rotifers (Asplanchna girodi and Brachionus calyciflorus) was studied using Asplanchna predatory behavior as an endpoint. The experimental design included three treatments: prey and predator exposure, only prey exposure, and only predator exposure. This enabled us to distinguish toxic effects on the predator from those on the prey and to

  1. Effects of an Infectious Fungus, Batrachochytrium dendrobatidis, on Amphibian Predator-Prey Interactions

    Microsoft Academic Search

    Barbara A. Han; Catherine L. Searle; Andrew R. Blaustein; Howard Browman

    2011-01-01

    The effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. We examined the effects of an emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. We also investigated

  2. Predator-Prey Interactions in Communities with prey dispersal and Allee effects

    E-print Network

    Berezovskaya, F; Castillo-Chavez, C

    2009-01-01

    The population dynamics of predator-prey systems in the presence of patch-specific predators are explored in a setting where the prey population has access to both habitats. The emphasis is in situations where patch-prey abundance drives prey-dispersal between patches, with the fragile prey populations, that is, populations subject to the Allee effect. The resulting four-dimensional model's mathematical analysis is carried out via sub-models that focus in lower dimensional settings. The outcomes depend on, and in fact they are quite sensitive to, the structure of the system, the range of parameter values, and initial conditions. We show that the system can support multi-stability and a diverse set of predator-prey life-history dynamics that includes rather complex dynamical system outcomes. It is argued that in general evolution should favor heterogeneous settings including Allee effects, prey-refuges, and patch-specific predators.

  3. Predator-Prey Interactions in Communities with prey dispersal and Allee effects

    Microsoft Academic Search

    F. Berezovskaya; S. Wirkus; C. Castillo-Chavez

    2009-01-01

    The population dynamics of predator-prey systems in the presence of patch-specific predators are explored in a setting where the prey population has access to both habitats. The emphasis is in situations where patch-prey abundance drives prey-dispersal between patches, with the fragile prey populations, that is, populations subject to the Allee effect. The resulting four-dimensional model's mathematical analysis is carried out

  4. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation.

    SciTech Connect

    J. L . Orrock; B. J. Danielson; M. J. Burns; D. J. Levey

    2003-02-03

    J.L. Orrock, B.J. Danielson, M.J. Burns, and D.J. Levey. 2003. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation. Ecology, 84(10):2589-2599. Abstract: Corridors that connect patches of disjunct habitat may be promising tools for mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes, we examined how corridors affect the impact of invertebrate, rodent, and avian seed predators on pokeweed, Phytolacca americana. Over 13 months in 2000 and 2001, we quantified the effects of patch shape, connectivity, and predator type on the number of seeds germinating in the field (germinants), seed removal, and the viability of remaining seeds. Corridors did not affect the number of P. americana germinants in experimental exclosures or the viability of seeds remaining in exclosures. However, corridors affected the removal of seeds in a predator-specific manner: invertebrates removed more seeds in unconnected patches, whereas rodents removed more seeds in connected patches. Seed removal by birds was similar in connected and unconnected patches. Total seed removal by all seed predators was not affected by corridors, because invertebrates removed more seeds where rodents removed fewer seeds, and vice versa. Overall, seed predation signi®cantly reduced the number and viability of remaining seeds, and reduced the number of germinants in 2000 but not in 2001. The abundance of naturally occurring P. americana plants in our experimental patches in 2000 decreased with increasing seed removal from exclosures but was not related to viability or germinants in 2000, suggesting that seed removal may shape the distribution and abundance of this species. Complementary patterns of seed removal by rodents and invertebrates suggest that corridors alter the effects of these predator taxa by changing the relative amounts of edge and core (nonedge) habitats in a patch. Because invertebrates and rodents do not completely overlap in the seeds they consume, corridors may change predation pressure on seeds that are primarily consumed by one predator type, with potential consequences for the composition of plant and seed predator communities.

  5. Accepted Manuscript Qualitative behaviour of n-dimensional ratio-dependent predator-prey systems

    E-print Network

    Tóth, János

    -dependent predator-prey interaction. Key words and phrases: Predator-prey system, Functional response, Sign stabilityAccepted Manuscript Qualitative behaviour of n-dimensional ratio-dependent predator-prey systems Pleasecitethisarticleas: K. Kiss,S.Kovács, Qualitativebehaviour of n-dimensional ratio-dependent predator-prey systems

  6. Predator-Prey Interactions of Dictyostelium discoideum and Escherichia coli in Continuous Culture1

    PubMed Central

    Tsuchiya, H. M.; Drake, J. F.; Jost, J. L.; Fredrickson, A. G.

    1972-01-01

    Dictyostelium discoideum and Escherichia coli were aerobically propagated in mixed continuous culture in a predator-prey relationship, and the effects of temperature and holding times were examined. Oscillations developed in the concentration of glucose, the limiting substrate for E. coli, and in the densities of the two populations, but eventually steady-state populations were reached. The experimental data were analyzed according to the Lotka-Volterra model for prey-predator relationships and by the Monod model for saturation kinetics. A comparison of the adequacy of the two models in describing predation is given. PMID:4555407

  7. Modelling the Dynamics of the Work-Employment System by Predator-Prey Interactions

    E-print Network

    Serpa, Nilo

    2011-01-01

    The broad application range of the predator-prey modelling enabled us to apply it to represent the dynamics of the work-employment system. For the adopted period, we conclude that this dynamics is chaotic in the beginning of the time series and tends to less perturbed states, as time goes by, due to public policies and hidden intrinsic system features. Basic Lotka-Volterra approach was revised and adapted to the reality of the study. The final aim is to provide managers with generalized theoretical elements that allow to a more accurate understanding of the behavior of the work-employment system.

  8. Predator–prey interactions between Synbranchus marmoratus (Teleostei: Synbranchidae) and Hypsiboas pulchellus tadpoles (Amphibia: Hylidae): Importance of lateral line in nocturnal predation and effects of fenitrothion exposure

    Microsoft Academic Search

    Celina M. Junges; Rafael C. Lajmanovich; Paola M. Peltzer; Andres M. Attademo; Agustín Bassó

    Environmental contaminants can disrupt interactions between aquatic species by altering community structure. We explored predator–prey interactions between marbled swamp juvenile eels (Synbranchus marmoratus; predator) and anuran tadpoles (Hypsiboas pulchellus; prey) in relation to two aspects: the importance of lateral line in the predator and whether the absence of light modifies predation rates; and the effect of a sub-lethal concentration of

  9. Predator-prey spatial game as a tool to understand the effects of protected areas on harvester-wildlife interactions.

    PubMed

    Tolon, Vincent; Martin, Jodie; Dray, Stéphane; Loison, Anne; Fischer, Claude; Baubet, Eric

    2012-03-01

    No-take reserves are sometimes implemented for sustainable population harvesting because they offer opportunities for animals to spatially avoid harvesters, whereas harvesters can benefit in return from the reserve spillover. Here, we used the framework of predator-prey spatial games to understand how protected areas shape spatial interactions between harvesters and target species and determine animal mortality. In these spatial games, the "predator" searches for "prey" and matches their habitat use, unless it meets spatial constraints offering the opportunity for prey to avoid the mortality source. However, such prey refuges could attract predators in the surroundings, which questions the potential benefits for prey. We located, in the Geneva Basin (France), hunting dogs and wild boar Sus scrofa L. during hunting seasons with global positioning systems and very-high-frequency collars. We quantified how the proximity of the reserve shaped the matching between both habitat uses using multivariate analyses and linked these patterns to animals' mortality with a Cox regression analysis. Results showed that habitat uses by both protagonists disassociated only when hunters were spatially constrained by the reserve. In response, hunters increased hunting efforts near the reserve boundary, which induced a higher risk exposure for animals settled over the reserve. The mortality of adult wild boar decreased near the reserve as the mismatch between both habitat uses increased. However the opposite pattern was determined for younger individuals that suffered from the high level of hunting close to the reserve. The predator-prey analogy was an accurate prediction of how the protected area modified spatial relationships between harvesters and target species. Prey-searching strategies adopted by hunters around reserves strongly impacted animal mortality and the efficiency of the protected area for this harvested species. Increasing reserve sizes and/or implementing buffer areas with harvesting limitations can dampen this edge effect and helps harvesters to benefit durably from source populations of reserves. Predator-prey spatial games therefore provide a powerful theoretical background for understanding wildlife-harvester spatial interactions and developing substantial application for sustainable harvesting. PMID:22611861

  10. Predator–prey interaction between hatchery-reared Japanese flounder juvenile, Paralichthys olivaceus, and sandy shore crab, Matuta lunaris: daily rhythms, anti-predator conditioning and starvation

    Microsoft Academic Search

    Mostafa A. R Hossain; Masaru Tanaka; Reiji Masuda

    2002-01-01

    Predator–prey interaction between sandy shore crab, Matuta lunaris (Forskål, 1775), and juvenile Japanese flounder, Paralichthys olivaceus (Temminck et Schlegel), was investigated under controlled laboratory conditions. Possibility of training and conditioning hatchery-reared flounder to avoid predators was also examined. Crabs took over 75% of their daily ration at night when they were given access to prey 24 h a day. Large

  11. Effects of aroclor 1254 and No. 2 fuel oil, singly and in combination, on predator-prey interactions in coho salmon ( Oncorhynchus kisutch )

    Microsoft Academic Search

    Leroy C. Folmar; Harold O. Hodgins

    1982-01-01

    The effects of No. 2 fuel oil on predator-prey interactions of coho salmon were examined. Since aquatic organisms under natural conditions are simultaneously exposed to more than one toxicant, the effects of fuel oil plus polychlorinated biphenyls (PCBs) were also evaluated. Experimental fish were either injected with a single intraperitoneal dose of 150 g\\/kg Aroclor 1254, exposed to fuel oil

  12. Hydrodynamic mediation of predator–prey interactions: differential patterns of prey susceptibility and predator success explained by variation in water flow

    Microsoft Academic Search

    Sean P. Powers; John N. Kittinger

    2002-01-01

    In most shallow water marine systems, fluid movements vary on scales that may influence local community dynamics both directly, through changes in the abundance of species, and indirectly, by modifying important behaviors of organisms. We examined how differences in current speed affect the outcome of predator–prey interactions for two species of marine benthic predators (knobbed whelks, Busycon carica, and blue

  13. Effects of an infectious fungus, Batrachochytrium dendrobatidis, on amphibian predator-prey interactions.

    PubMed

    Han, Barbara A; Searle, Catherine L; Blaustein, Andrew R

    2011-01-01

    The effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. We examined the effects of an emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. We also investigated whether amphibian predators consumed infected prey, and whether B. dendrobatidis caused differences in predation rates among prey in laboratory feeding trials. We found differences in anti-predator behaviors among larvae of four amphibian species, and show that infected tadpoles of one species (Anaxyrus boreas) were more active and sought refuge more frequently when exposed to predator chemical cues. Salamander predators consumed infected and uninfected tadpoles of three other prey species at similar rates in feeding trials, and predation risk among prey was unaffected by B. dendrobatidis. Collectively, our results show that even sub-lethal exposure to B. dendrobatidis can alter fundamental anti-predator behaviors in some amphibian prey species, and suggest the unexplored possibility that indiscriminate predation between infected and uninfected prey (i.e., non-selective predation) could increase the prevalence of this widely distributed pathogen in amphibian populations. Because one of the most prominent types of predators in many amphibian systems is salamanders, and because salamanders are susceptible to B. dendrobatidis, our work suggests the importance of considering host susceptibility and behavioral changes that could arise from infection in both predators and prey. PMID:21311771

  14. Predator–prey interactions between a planktonic ciliate Strombidium sp. (Ciliophora, Oligotrichida) and the dinoflagellate Pfiesteria piscicida (Dinamoebiales, Pyrrophyta)

    Microsoft Academic Search

    Outi Setälä; Riitta Autio; Harri Kuosa

    2005-01-01

    The functional response of a planktonic ciliate, Strombidium sp. feeding on the dinoflagellate Pfiesteria piscicida non-toxic zoospores (NTZ) was experimentally studied with four different prey concentrations (43–3153cellsml?1). Data from direct observations (NTZ inside individual Strombidium sp.) was used to calculate predator–prey specific ingestion and clearance rates. The ingestion rates varied between 0.68 and 14.26NTZind?1h?1, and with the predator–prey specific handling

  15. Stochastic predator-prey models: Population oscillations, spatial correlations,

    E-print Network

    Wirosoetisno, Djoko

    NSF-DMR 0308548, IAESTE #12;Outline · Introductory remarks · Lotka-Volterra predator-prey interaction interaction · predators: A 0 death, rate · prey: B B+B birth, rate · predation: A+B A+A, rate (AStochastic predator-prey models: Population oscillations, spatial correlations, and the effect

  16. Coevolution can reverse predator–prey cycles

    PubMed Central

    Cortez, Michael H.; Weitz, Joshua S.

    2014-01-01

    A hallmark of Lotka–Volterra models, and other ecological models of predator–prey interactions, is that in predator–prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator–prey coevolution can also drive population cycles where the opposite of canonical Lotka–Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage–cholera, mink–muskrat, and gyrfalcon–rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator–prey coevolution and reveal unique ways in which predator–prey coevolution can shape, and possibly reverse, community dynamics. PMID:24799689

  17. Computational Science Technical Note CSTN-010 Defensive Spiral Emergence in a Predator-Prey Model

    E-print Network

    Hawick, Ken

    behaviour that arises from the predator- prey interactions. We believe the emergent patterns from predator-prey interaction between randomly initialised groups of animal automata. We believe we0 Computational Science Technical Note CSTN-010 Defensive Spiral Emergence in a Predator-Prey Model

  18. GLOBAL ANALYSIS IN A PREDATOR-PREY SYSTEM WITH NONMONOTONIC FUNCTIONAL RESPONSE

    E-print Network

    Ruan, Shigui

    and by Volterra in 1926 in modeling a predator-prey interaction. However, the curve defined by the Lotka­ VolterraGLOBAL ANALYSIS IN A PREDATOR-PREY SYSTEM WITH NONMONOTONIC FUNCTIONAL RESPONSE SHIGUI RUAN. 1445­1472 Abstract. A predator-prey system with nonmonotonic functional response is considered. Global

  19. Lotka-Volterra Predator-Prey Model Prey V(t), Predator P(t)

    E-print Network

    Caraco, Thomas

    (interactions) at one scale can induce pattern at extended spatio-temporal scales. #12;Example: Predator-PreyLotka-Volterra Predator-Prey Model Prey V(t), Predator P(t) Equilibrium Nodes: (0, 0) and (V* = D Temporal Behavior #12;Ricklefs and Miller, 2000 Ecology #12;Examine Neutral Stability, Predator-Prey

  20. RESOURCE COMPETITION MODIFIES THE STRENGTH OF TRAIT-MEDIATED PREDATOR–PREY INTERACTIONS: A META-ANALYSIS

    Microsoft Academic Search

    Daniel I. Bolnick; Evan L. Preisser

    2005-01-01

    Only a fraction of the individuals in a given prey population are likely to be killed and consumed by predators. In contrast, nearly all individuals experience the chronic effects of predation risk. When threatened by predators, prey adopt defensive tactics whose costs can lead to reduced growth, maturation rates, survivorship, fecundity, or pop- ulation density. This nonconsumptive impact of predation

  1. Bottom-up meets top-down: leaf litter inputs influence predator-prey interactions in wetlands.

    PubMed

    Stoler, Aaron B; Relyea, Rick A

    2013-09-01

    While the common conceptual role of resource subsidies is one of bottom-up nutrient and energy supply, inputs can also alter the structural complexity of environments. This can further impact resource flow by providing refuge for prey and decreasing predation rates. However, the direct influence of different organic subsidies on predator-prey dynamics is rarely examined. In forested wetlands, leaf litter inputs are a dominant energy and nutrient resource and they can also increase benthic surface cover and decrease water clarity, which may provide refugia for prey and subsequently reduce predation rates. In outdoor mesocosms, we investigated how inputs of leaf litter that alter benthic surface cover and water clarity influence the mortality and growth of gray treefrog tadpoles (Hyla versicolor) in the presence of free-swimming adult newts (Notophthalmus viridiscens), which are visual predators. To manipulate surface cover, we added either oak (Quercus spp.) or red pine (Pinus resinosa) litter and crossed these treatments with three levels of red maple (Acer rubrum) litter leachate to manipulate water clarity. In contrast to our predictions, benthic surface cover had no effect on tadpole survival while darkening the water caused lower survival. In addition, individual tadpole mass was lowest in the high maple leachate treatments, suggesting an interaction between bottom-up effects of leaf litter and top-down effects of predation risk that altered mortality and growth of tadpoles. Our results indicate that realistic changes in forest tree composition, which cause concomitant changes in litter inputs to wetlands, can substantially alter community interactions. PMID:23386045

  2. From the Cover: Community-wide distribution of predator-prey interaction strength in kelp forests

    Microsoft Academic Search

    Enric Sala; Michael H. Graham

    2002-01-01

    The strength of interactions between predators and their prey (interaction strength) varies enormously among species within ecological communities. Understanding the community-wide distribution of interaction strengths is vital, given that communities dominated by weak interactions may be more stable and resistant to invasion. In the oceans, previous studies have reported log-normal distributions of per capita interaction strength. We estimated the distribution

  3. Application of nonlinear stability theory to the study of the effects of diffusion on predator-prey interactions

    Microsoft Academic Search

    Lee A. Segel; Simon A. Levin

    1976-01-01

    In the basic predator-prey model under investigation, growth rates of both species are influenced by both predator and prey population levels. Random dispersal is modelled by diffusion-like terms in both discrete and continuous situations. Application of a combined successive-approximations multiple-scale approach to stability theory shows that under some circumstances uniform conditions will be succeeded by a new steady state wherein

  4. The Coevolution of Predator--Prey Interactions: ESSS and Red Queen Dynamics

    Microsoft Academic Search

    Paul Marrow; Richard Law; C. Cannings

    1992-01-01

    A model for the coevolution of body size of predators and their prey is described. Body sizes are assumed to affect the interactions between individuals, and the Lotka-Volterra population dynamics arising from these interactions provide the driving force for evolutionary change. The space of phenotypes of predator and prey contains a region, oval in shape, in which the predator and

  5. Effect of Culverts on Predator-Prey Interactions in a Tropical Stream

    Microsoft Academic Search

    C. L. Hein; D. A. Kikkert; T. A. Crowl

    2005-01-01

    As part of a biocomplexity project in Puerto Rico, we use river and road networks as a platform to understand the interactions between stream biota, the physical environment, and human activity. Specifically, we ask if humans affect aquatic organisms through road building and recreational activities. Culverts have been documented to impede or slow migration of aquatic biota. This is especially

  6. Comparison of predator–prey interaction models for fish assemblages from the neotropical region

    Microsoft Academic Search

    P. A. Piana; L. C. Gomes; A. A. Agostinho

    2006-01-01

    Predation is one of the main fish assemblages structuring force in many aquatic ecosystems. Finding a functional relationship between predator and prey that improves our understanding of this process is a challenge to ecologists. In order to evaluate this interaction, several models have been created, each one of them representing a specific biological mechanism. Although, these models have not been

  7. SCARED TO DEATH? THE EFFECTS OF INTIMIDATION AND CONSUMPTION IN PREDATOR–PREY INTERACTIONS

    Microsoft Academic Search

    Evan L. Preisser; Daniel I. Bolnick; Michael F. Benard

    2005-01-01

    Predation is a central feature of ecological communities. Most theoretical and empirical studies of predation focus on the consequences of predators consuming their prey. Predators reduce prey population densities through direct consumption (a density- mediated interaction, DMI), a process that may indirectly affect the prey's resources, com- petitors, and other predators. However, predators can also affect prey population density by

  8. Habitat structure and prey aggregation determine the functional response in a soil predator–prey interaction

    Microsoft Academic Search

    Olivera Vucic-Pestic; Klaus Birkhofer; Björn C. Rall; Stefan Scheu; Ulrich Brose

    2010-01-01

    Functional responses describe the per capita consumption rates of predators depending on prey density, which quantifies the energy transfer between trophic levels. We studied a typical interaction of the litter–soil systems between hunting spiders (Pardosa lugubris; Araneae: Lycosidae) and springtails (Heteromurus nitidus; Collembola: Entomobryidae) at varying habitat structure, i.e. with moss vs. without moss. We found a hyperbolic increase in

  9. Pesticide impacts on predator-prey interactions across two levels of organisation.

    PubMed

    Rasmussen, Jes Jessen; Nørum, Ulrik; Jerris, Morten Rygaard; Wiberg-Larsen, Peter; Kristensen, Esben Astrup; Friberg, Nikolai

    2013-09-15

    In this study, we aimed to evaluate the effects of a short pulse exposure of the pyrethroid lambda-cyhalothrin (LC) on the predator and anti-predator behaviour of the same species; Gammarus pulex. Predator behaviour, at the level of the individual, was studied in indoor microcosms using video tracking equipment during simultaneous exposure of the predator (G. pulex) and its prey (Leuctra nigra) during 90 min exposure of 1, 6.6 or 62.1 ngL(-1) LC. During an initial 30 min of exposure, the predator and prey organisms were maintained physically separated, and the actual interaction was studied through the subsequent 60 min of exposure. The anti-predator behaviour of G. pulex (drift suppression in response to the presence of brown trout) was studied in outdoor stream channels during a 90 min pulse exposure to LC (7.4 or 79.5 ngL(-1)) with, or without, brown trout. Based on survival curves for L. nigra we found that the mortality rate for L. nigra significantly decreased during exposure to 6.6 and 62.1 ngL(-1) LC (P<0.05 and P<0.001, respectively). We found no significant effects suggesting that G. pulex was repelled by contaminated prey items (P>0.05). We found that the exposure of G. pulex to 7.4 and 79.5 ngL(-1) LC significantly increased drift (from ?0% to ?100% in both treatments; P<0.001) independent of the presence of brown trout (P<0.05). In other words, the natural anti-predator behaviour of G. pulex was overruled by the stress response to LC exposure increasing G. pulex predation risk from drift feeding brown trouts. Our results show that the anti-predator and predator behaviour of G. pulex were significantly changed during exposure to very low and environmentally realistic LC concentrations and exposure duration. The potential implications for the field scenario are discussed. PMID:23891783

  10. Quasicycles in a spatial predator-prey model Carlos A. Lugo and Alan J. McKane*

    E-print Network

    McKane, Alan

    models of simple predator-prey interactions to predict that predator and prey numbers oscillate in time- tem where the interaction between individuals of those spe- cies is of the predator-prey typeQuasicycles in a spatial predator-prey model Carlos A. Lugo and Alan J. McKane* Theoretical Physics

  11. Relaxation oscillation profile of limit cycle in predator-prey Department of Mathematics, National Tsing Hua University, Hsinchu, Taiwan

    E-print Network

    Hsu, Sze-Bi

    model 1 Introduction For a class of conventional predator-prey interaction models, it is knownRelaxation oscillation profile of limit cycle in predator-prey system Sze-Bi Hsu Department It is known that some predator-prey system can possess a unique limit cycle which is globally asymptotically

  12. Unusual predator-prey dynamics under reciprocal phenotypic plasticity.

    PubMed

    Mougi, Akihiko

    2012-07-21

    Recent theories and experiments have shown that plasticity, such as an inducible defense or an inducible offense in predator-prey interactions, strongly influences the stability of the population dynamics. However, such plastic adaptation has not been expected to cause unusual dynamics such as antiphase cycles, which occur in experimental predator-prey systems with evolutionary adaptation in the defensive trait of prey. Here I show that antiphase cycles and cryptic cycles (a large population fluctuation in one species with almost no change in the population of the other species) can occur in a predator-prey system when both member species can change their phenotypes through adaptive plasticity (inducible defenses and offenses). I consider a familiar type of predator-prey system in which both species can change their morphology or behavior through phenotypic plasticity. The plasticity, that is, the ability to change between distinct phenotypes, is assumed to occur so as to maximize their fitness. I examined how the reciprocal adaptive plasticity influences the population dynamics. The results show that unusual dynamics such as antiphase population cycles and cryptic cycles can occur when both species show inducible plasticity. The unusual dynamics are particularly likely to occur when the carrying capacity of the prey is small (the density dependence of the prey's growth is strong). The unusual predator-prey dynamics may be induced by phenotypic plasticity as long as the phenotypic change occurs to maximize fitness. PMID:22575552

  13. Chemotactic predator-prey dynamics

    NASA Astrophysics Data System (ADS)

    Sengupta, Ankush; Kruppa, Tobias; Löwen, Hartmut

    2011-03-01

    A discrete chemotactic predator-prey model is proposed in which the prey secrets a diffusing chemical which is sensed by the predator and vice versa. Two dynamical states corresponding to catching and escaping are identified and it is shown that steady hunting is unstable. For the escape process, the predator-prey distance is diffusive for short times but exhibits a transient subdiffusive behavior which scales as a power law t1/3 with time t and ultimately crosses over to diffusion again. This allows us to classify the motility and dynamics of various predatory microbes and phagocytes. In particular, there is a distinct region in the parameter space where they prove to be infallible predators.

  14. Wave Train Selection Behind Invasion Fronts in Reaction-Diffusion Predator-Prey Models

    E-print Network

    Nagata, Wayne

    is that this oscillatory behaviour arises from the interaction between a predator population and its prey, and many modelsWave Train Selection Behind Invasion Fronts in Reaction-Diffusion Predator-Prey Models Sandra M in oscillatory reaction-diffusion models for predator-prey systems. Although there is a one-parameter family

  15. The Role of Space in Reducing PredatorPrey Cycles

    E-print Network

    .1 Introduction Throughout the history of ecology, the interaction between predators and their prey has received-based models. We then present a simple two-patch model for predator­prey interaction, followed by a gen of interacting predator and prey individ- uals, one needs to keep track of all individuals and their positions

  16. On Global Stability of a Predator-Prey System Department of Mathematics, University of Utah, Salt Lake City, Utah, 84Il2

    E-print Network

    Hsu, Sze-Bi

    -dimensional model for predator-prey interaction is proposed. Two criteria for global stability of the locally stableOn Global Stability of a Predator-Prey System S. B. HSU Department of Mathematics, University of a predator-prey model discussed in [2]. In that paper, Freedman proved the graphical stability criteria

  17. A global mathematical investigation of a predator-prey model

    E-print Network

    S. A. Treskov; E. P. Volokitin

    2009-11-05

    We construct a global bifurcation diagram of the plane differential system $$ {l} \\dot x = x(1-x)-x y/(a+x^2), \\dot y = y(\\delta-\\beta y/x), x(t)>0, y(t)>0, a>0, \\delta>0, \\beta>0, $$ which describes the predator-prey interaction.

  18. Biological control of two-spotted spider mites using phytoseiid predators. Part I. Modelling the predator-prey interaction at the individual level

    Microsoft Academic Search

    M. W. Sabelis

    1982-01-01

    The searching behaviour of individual predators of four phytoseiid species ( Phytoseiulus persimilis , Amblyseius p o tentillae , Amblyseius bibens , Metaseiulus occidentalis ) is investigated in relation to the two-spotted spider mite ( Tetranychus urticae ), which infests greenhouse roses. Especially the role of spider- mite webbing in the predator-prey relation is studied. Webbing interferes with searching, decreasing

  19. The impact of environmental toxins on predator-prey dynamics.

    PubMed

    Huang, Qihua; Wang, Hao; Lewis, Mark A

    2015-08-01

    Predators and prey may be simultaneously exposed to environmental toxins, but one may be more susceptible than the other. To study the effects of environmental toxins on food web dynamics, we develop a toxin-dependent predator-prey model that combines both direct and indirect toxic effects on two trophic levels. The direct effects of toxins typically reduce organism abundance by increasing mortality or reducing fecundity. Such direct effects, therefore, alter both bottom-up food availability and top-down predatory ability. However, the indirect effects, when mediated through predator-prey interactions, may lead to counterintuitive effects. This study investigates how the balance of the classical predator-prey dynamics changes as a function of environmental toxin levels. While high toxin concentrations are shown to be harmful to both species, possibly leading to extirpation of both species, intermediate toxin concentrations may affect predators disproportionately through biomagnification, leading to reduced abundance of predators and increased abundance of the prey. This counterintuitive effect significantly increases biomass at the lower trophic level. Environmental toxins may also reduce population variability by preventing populations from fluctuating around a coexistence equilibrium. Finally, environmental toxins may induce bistable dynamics, in which different initial population levels produce different long-term outcomes. Since our toxin-dependent predator-prey model is general, the theory developed here not only provides a sound foundation for population or community effects of toxicity, but also could be used to help develop management strategies to preserve and restore the integrity of contaminated habitats. PMID:25916557

  20. Spatial dynamics in a predator-prey model with herd behavior

    NASA Astrophysics Data System (ADS)

    Yuan, Sanling; Xu, Chaoqun; Zhang, Tonghua

    2013-09-01

    In this paper, a spatial predator-prey model with herd behavior in prey population and quadratic mortality in predator population is investigated. By the linear stability analysis, we obtain the condition for stationary pattern. Moreover, using standard multiple-scale analysis, we establish the amplitude equations for the excited modes, which determine the stability of amplitudes towards uniform and inhomogeneous perturbations. By numerical simulations, we find that the model exhibits complex pattern replication: spotted pattern, stripe pattern, and coexistence of the two. The results may enrich the pattern dynamics in predator-prey models and help us to better understand the dynamics of predator-prey interactions in a real environment.

  1. Predator\\/prey interactions: A link between the individual level and both higher and lower level effects of toxicants in aquatic ecosystems

    Microsoft Academic Search

    Judith S. Weis; Graeme Smith; Celine Santiago-Bass

    2000-01-01

    Behavior can demonstrate linkages ofcontaminant effects at different levels oforganization from the biochemical\\/cellular to theorganism, population, and community levels.Mummichogs, Fundulus heteroclitus, from acontaminated area were previously found to havereduced condition, growth, and longevity, comparedwith conspecifics from clean sites. Thispopulation-level observation may be due to theirimpaired predator\\/prey behavior, which is associatedwith altered levels of serotonin in their brains. Theyare slow, less

  2. Evolutionary ecology of inducible morphological plasticity in predator–prey interaction: toward the practical links with population ecology

    Microsoft Academic Search

    Osamu Kishida; Geoffrey C. Trussell; Akihiko Mougi; Kinya Nishimura

    2010-01-01

    The outcome of species interactions is often strongly influenced by variation in the functional traits of the individuals\\u000a participating. A rather large body of work demonstrates that inducible morphological plasticity in predators and prey can\\u000a both influence and be influenced by species interaction strength, with important consequences for individual fitness. Much\\u000a of the past research in this area has focused

  3. HOW TO MANAGE NATURE? STRATEGIES, PREDATOR-PREY MODELS, AND CHAOS

    Microsoft Academic Search

    R. Quentin Grafton; J. Silva-Echenique

    1997-01-01

    The Lotka-Volterra predator-prey model exemplifies the implicit and explicit assumptions managers often have regarding species interaction � populations are stable or fluctuate periodically. The reality is often much more complicated and there is overwhelming evidence that many populations fluctuate in a nonperiodic way. Using a discrete predator-prey model that generates chaos, it is possible to qualitatively mimic the interaction of

  4. Effects of Temperature and Turbulence on the Predator–Prey Interactions between a Heterotrophic Flagellate and a Marine Bacterium

    Microsoft Academic Search

    M. P. Delaney

    2003-01-01

    Biotic and abiotic factors can influence interactions between microbial grazers and their prey, thus impacting both the cycling of biogenic carbon within the surface layer of the ocean and the export of carbon to the deep ocean and higher trophic levels. In this study, microcosm experiments were used to evaluate the combined effect of temperature and turbulence on the growth

  5. Seasonal changes in infaunal community structure in a hypertrophic brackish canal: Effects of hypoxia, sulfide, and predator-prey interaction.

    PubMed

    Kanaya, Gen; Nakamura, Yasuo; Koizumi, Tomoyoshi; Yamada, Katsumasa

    2015-07-01

    We conducted a one-year survey of macrozoobenthic community structure at 5 stations in a eutrophic canal in inner Tokyo Bay, focusing on the impacts of hypoxia, sediment H2S, and species interaction in the littoral soft-bottom habitats. Complete defaunation or decreasing density of less-tolerant taxa occurred under hypoxia during warmer months, especially at subtidal or sulfidic stations; this was followed by rapid recolonization by opportunistic polychaetes in fall-winter. Sedimentary H2S increased the mortality of macroinvertebrates under hypoxia or delayed population recovery during recolonization. The density of several polychaetes (e.g., Pseudopolydora reticulata) declined in winter, coincident with immigration of the predator Armandia lanceolata. This suggests that absence of A. lanceolata under moderate hypoxia enabled the proliferation of prey taxa. We conclude that oxygen concentration, sediment H2S, and hypoxia-induced changes in species interactions are potential drivers for spatiotemporal changes in macrozoobenthic assemblage structure in hypoxia-prone soft-bottom communities. PMID:25925266

  6. Probability of detecting marine predator-prey and species interactions using novel hybrid acoustic transmitter-receiver tags.

    PubMed

    Baker, Laurie L; Jonsen, Ian D; Mills Flemming, Joanna E; Lidgard, Damian C; Bowen, William D; Iverson, Sara J; Webber, Dale M

    2014-01-01

    Understanding the nature of inter-specific and conspecific interactions in the ocean is challenging because direct observation is usually impossible. The development of dual transmitter/receivers, Vemco Mobile Transceivers (VMT), and satellite-linked (e.g. GPS) tags provides a unique opportunity to better understand between and within species interactions in space and time. Quantifying the uncertainty associated with detecting a tagged animal, particularly under varying field conditions, is vital for making accurate biological inferences when using VMTs. We evaluated the detection efficiency of VMTs deployed on grey seals, Halichoerus grypus, off Sable Island (NS, Canada) in relation to environmental characteristics and seal behaviour using generalized linear models (GLM) to explore both post-processed detection data and summarized raw VMT data. When considering only post-processed detection data, only about half of expected detections were recorded at best even when two VMT-tagged seals were estimated to be within 50-200 m of one another. At a separation of 400 m, only about 15% of expected detections were recorded. In contrast, when incomplete transmissions from the summarized raw data were also considered, the ratio of complete transmission to complete and incomplete transmissions was about 70% for distances ranging from 50-1000 m, with a minimum of around 40% at 600 m and a maximum of about 85% at 50 m. Distance between seals, wind stress, and depth were the most important predictors of detection efficiency. Access to the raw VMT data allowed us to focus on the physical and environmental factors that limit a transceiver's ability to resolve a transmitter's identity. PMID:24892286

  7. Applying IR Tomo PIV and 3D Organism Tracking to Study Turbulence Effects on Oceanic Predator-Prey Interactions

    NASA Astrophysics Data System (ADS)

    Adhikari, Deepak; Hallberg, Michael; Gemmell, Brad; Longmire, Ellen; Buskey, Edward

    2012-11-01

    The behavorial response of aquatic predators and prey depends strongly on the surrounding fluid motion. We present a facility and non-intrusive instrumentation system designed to quantify the motions associated with interactions between small coral reef fish (blennies) and evasive zooplankton prey (copepod) subject to various flow disturbances. A recirculating water channel facility is driven by a paddlewheel to prevent damaging the zooplankton located throughout the channel. Fluid velocity vectors surrounding both species are determined by time-resolved infrared tomographic PIV, while a circular Hough transform and PTV technique is used to track the fish eye in three-dimensional space. Simultaneously, zooplankton motions are detected and tracked using two additional high-speed cameras with IR filters. For capturing larger scales, a measurement volume of 80 x 40 x 18 mm is used with spatial resolution of 3.5 mm. For capturing smaller scales, particularly for observing flow near the mouth of the fish during feeding, the measurement volume is reduced to 20 × 18 × 18 mm with spatial resolution of 1.5 mm. Results will be presented for both freshwater and seawater species. Supported by NSF IDBR grant #0852875.

  8. Cascade of Complexity in Evolving Predator-Prey Dynamics

    NASA Astrophysics Data System (ADS)

    Guttenberg, Nicholas; Goldenfeld, Nigel

    2008-02-01

    We simulate an individual-based model that represents both the phenotype and genome of digital organisms with predator-prey interactions. We show how open-ended growth of complexity arises from the invariance of genetic evolution operators with respect to changes in the complexity, and that the dynamics which emerges shows scaling indicative of a nonequilibrium critical point. The mechanism is analogous to the development of the cascade in fluid turbulence.

  9. Mathematical Models Of Predator-Prey Systems

    E-print Network

    Linder, Tamás

    ) = BCNP - DP #12;Diffusion Driven Instability ? Without the diffusion terms the stable equilibrium are N conditions required for diffusion-driven instability. They are fNd + gP > 0 and f2 Nd2 + 2d(fNgP - fPgN) + g2Mathematical Models Of Predator-Prey Systems Bobby, Jostein, Shane, Jeff, Majid, Carly, Jay

  10. Dynamics in a ratio-dependent predator-prey model with predator harvesting

    NASA Astrophysics Data System (ADS)

    Xiao, Dongmei; Li, Wenxia; Han, Maoan

    2006-12-01

    The objective of this paper is to study systematically the dynamical properties of a ratio-dependent predator-prey model with nonzero constant rate predator harvesting. It is shown that the model has at most two equilibria in the first quadrant and can exhibit numerous kinds of bifurcation phenomena, including the bifurcation of cusp type of codimension 2 (i.e., Bogdanov-Takens bifurcation), the subcritical and supercritical Hopf bifurcations. These results reveal far richer dynamics compared to the model with no harvesting and different dynamics compared to the model with nonzero constant rate prey harvesting in [D. Xiao, L. Jennings, Bifurcations of a ratio-dependent predator-prey system with constant rate harvesting, SIAM Appl. Math. 65 (2005) 737-753]. Biologically, it is shown that nonzero constant rate predator harvesting can prevent mutual extinction as a possible outcome of the predator prey interaction, and remove the singularity of the origin, which was regarded as "pathological behavior" for a ratio-dependent predator prey model in [P. Yodzis, Predator-prey theory and management of multispecies fisheries, Ecological Applications 4 (2004) 51-58].

  11. Predator-prey-substrate model of wastewater treatment in bioreactor system

    NASA Astrophysics Data System (ADS)

    Sadikin, Zubaidah; Salim, Normah; Allias, Razihan

    2013-04-01

    This paper analyses the mathematical model of the interaction between predator-prey and substrate that have been expressed as a system of nonlinear ordinary differential equations. This mathematical model can help to investigate the biological reaction of the interaction of predator-prey and substrate in biological wastewater treatment to improve the quality of water that flows out from the reactor. By using Monod Kinetics Growth Model, the steady state solutions have been obtained and their stability is determined as a function of the residence time.

  12. arXiv:1105.3662v1[math.DS]18May2011 Nonlocal Generalized Models of Predator-Prey Systems

    E-print Network

    a plethora of models that aim at capturing the interaction between a predator population Y and a preyarXiv:1105.3662v1[math.DS]18May2011 Nonlocal Generalized Models of Predator-Prey Systems Christian points. In this paper we analyze predator- prey dynamical systems and extend the method of generalized

  13. 3.11 Predator-Prey models Let )(tx be the population density of prey, )(ty be the population density of

    E-print Network

    Hsu, Sze-Bi

    density of predator at time t . The general model for predator-prey interaction is following ),( yxxf dt§3.11 Predator-Prey models Let )(tx be the population density of prey, )(ty be the population assume the prey grows exponentially in the absence of predation. The prey is consumed by predator

  14. A reduced model for spatially structured predator-prey systems with fast spatial migrations and slow

    E-print Network

    Castella, François

    evolving both under the effect of spatial migrations, and under the effect of prey-predator interaction. We interaction through a simple Lotka- Volterra system: we stress that any other realistic model of prey-predator, in this context, while the typical time-scale of predator-prey interaction is naturally of the order of several

  15. A reduced model for spatially structured predator-prey systems with fast spatial migrations and slow

    E-print Network

    Paris-Sud XI, Université de

    migrations, and under the effect of prey-predator interaction. We consider situations where prey-predator bounded domain. On the one hand, we choose to describe prey-predator interaction through a simple Lotka-scale of predator-prey interaction is naturally of the order of several weeks up to one year (it corresponds

  16. Anthropogenic resource subsidies decouple predator-prey relationships.

    PubMed

    Rodewald, Amanda D; Kearns, Laura J; Shustack, Daniel P

    2011-04-01

    The extent to which resource subsidies affect food web dynamics is poorly understood in anthropogenic landscapes. To better understand how species interactions are influenced by subsidies, we studied breeding birds and nest predators along a rural-to-urban landscape gradient that varied in subsidies provided to generalist predators. We hypothesized that resource subsidies in urban landscapes would decouple predator-prey relationships, as predators switch from natural to anthropogenic foods. From 2004 to 2009, we surveyed nest predators and monitored 2942 nests of five songbird species breeding in 19 mature forest stands in Ohio, USA. Eighteen species were video-recorded depredating nests. Numbers of avian and mammalian nest predators were positively associated with the amount of urban development surrounding forests, with the exception of Brown-headed Cowbirds (Molothrus ater). Although nest survival strongly declined with detections of nest predators in rural landscapes, nest survival and predator numbers were unrelated in urban landscapes. Thus, the strength of interaction between breeding birds and nest predators diminished as landscapes surrounding forested parks became more urbanized. Our work suggests that decoupling of predator-prey relationships can arise when synanthropic predators are heavily subsidized by anthropogenic resources. In this way, human drivers can alter, and completely disarticulate, relationships among species that are well established in more natural systems. PMID:21639056

  17. Supporting Information Appendix for PERSISTENT PREDATOR-PREY DYNAMICS REVEALED BY

    E-print Network

    Kammer, Thomas

    1 1 Supporting Information Appendix for PERSISTENT PREDATOR-PREY DYNAMICS REVEALED of taphonomic bias as well. As explained in the text, there is direct fossil evidence for predatory interactions the source of spurious correlations. Finally, if a third phenomenon were driving the apparent interaction

  18. The ecological play of predator–prey dynamics in an evolutionary theatre

    Microsoft Academic Search

    Marc T. J. Johnson; Anurag A. Agrawal

    2003-01-01

    Although over 40 years of theory have addressed how evolutionary processes can affect the ecology of predator–prey interactions, few empirical data have addressed the same issue. Shertzer et al. and Yoshida et al. have recently combined manipulative experiments with mathematical models to demonstrate that evolutionary change in an algal prey strongly affects community dynamics with their rotifer predator. These studies

  19. A Computer Simulation for Demonstrating and Modelling Predator-Prey Oscillations.

    ERIC Educational Resources Information Center

    Lutterschmidt, William I.; Schaefer, Jacob F.

    1997-01-01

    Discusses a computer simulation designed as an educational tool for students to observe predator-prey oscillations and experimentally investigate how changes in life histories affect predator and prey densities. Provides hands-on interaction with such theories and with mathematical models. Available to any instructor for curriculum use. (AIM)

  20. Dynamics and Equilibria of Ecological Predator-Prey Networks

    E-print Network

    Nagurney, Anna

    Dynamics and Equilibria of Ecological Predator-Prey Networks as Nature's Supply Chains Anna, Connecticut 06117 58th Annual North American Meetings of the Regional Science Association International Miami, Florida, November 9-12, 2011 Anna and Ladimer S. Nagurney Ecological Predator-Prey Networks #12

  1. Environmental versus demographic variability in stochastic predator-prey models

    NASA Astrophysics Data System (ADS)

    Dobramysl, U.; Täuber, U. C.

    2013-10-01

    In contrast to the neutral population cycles of the deterministic mean-field Lotka-Volterra rate equations, including spatial structure and stochastic noise in models for predator-prey interactions yields complex spatio-temporal structures associated with long-lived erratic population oscillations. Environmental variability in the form of quenched spatial randomness in the predation rates results in more localized activity patches. Our previous study showed that population fluctuations in rare favorable regions in turn cause a remarkable increase in the asymptotic densities of both predators and prey. Very intriguing features are found when variable interaction rates are affixed to individual particles rather than lattice sites. Stochastic dynamics with demographic variability in conjunction with inheritable predation efficiencies generate non-trivial time evolution for the predation rate distributions, yet with overall essentially neutral optimization.

  2. A Model-Based Approach to Predicting Predator-Prey & Friend-Foe Relationships in Ant Colonies

    E-print Network

    Narayanaswami, Karthik

    2009-01-01

    Understanding predator-prey relationships among insects is a challenging task in the domain of insect-colony research. This is due to several factors involved, such as determining whether a particular behavior is the result of a predator-prey interaction, a friend-foe interaction or another kind of interaction. In this paper, we analyze a series of predator-prey and friend-foe interactions in two colonies of carpenter ants to better understand and predict such behavior. Using the data gathered, we have also come up with a preliminary model for predicting such behavior under the specific conditions the experiment was conducted in. In this paper, we present the results of our data analysis as well as an overview of the processes involved.

  3. The direct and indirect effects of temperature on a predator–prey relationship

    Microsoft Academic Search

    Michael T. Anderson; Joseph M. Kiesecker; Douglas P. Chivers; Andrew R. Blaustein

    2001-01-01

    Abiotic factors may directly influence community structure by influencing biotic interactions. In aquatic systems, where gape-limited predators are common, abiotic factors that influence organisms' growth rates potentially mediate predator-prey interactions indirectly through effects on prey size. We tested the hypothesis that temperature influences interactions between aquatic size-limited insect predators ( Notonecta kirbyi) and their larval anuran prey (Hyla regilla) beyond

  4. Human Activity Helps Prey Win the Predator-Prey Space Race

    Microsoft Academic Search

    Tyler B. Muhly; Christina Semeniuk; Alessandro Massolo; Laura Hickman; Marco Musiani; Matjaz Perc

    2011-01-01

    Predator-prey interactions, including between large mammalian wildlife species, can be represented as a “space race”, where prey try to minimize and predators maximize spatial overlap. Human activity can also influence the distribution of wildlife species. In particular, high-human disturbance can displace large carnivore predators, a trait-mediated direct effect. Predator displacement by humans could then indirectly benefit prey species by reducing

  5. Evolution of dispersal in a predator-prey metacommunity.

    PubMed

    Pillai, Pradeep; Gonzalez, Andrew; Loreau, Michel

    2012-02-01

    Dispersal is crucial to allowing species inhabiting patchy or spatially subdivided habitats to persist globally despite the possibility of frequent local extinctions. Theoretical studies have repeatedly demonstrated that species that exhibit a regional metapopulation structure and are subject to increasing rates of local patch extinctions should experience strong selective pressures to disperse more rapidly despite the costs such increased dispersal would entail in terms of decreased local fitness. We extend these studies to consider how extinctions arising from predator-prey interactions affect the evolution of dispersal for species inhabiting a metacommunity. Specifically, we investigate how increasing a strong extinction-prone interaction between a predator and prey within local patches affects the evolution of each species' dispersal. We found that for the predator, as expected, evolutionarily stable strategy (ESS) dispersal rates increased monotonically in response to increasing local extinctions induced by strong predator top-down effects. Unexpectedly for the prey, however, ESS dispersal rates displayed a nonmonotonic response to increasing predator-induced extinction rates-actually decreasing for a significant range of values. These counterintuitive results arise from how extinctions resulting from trophic interactions play out at different spatial scales: interactions that increase extinction rates of both species locally can, at the same time, decrease the frequency of interaction between the prey and predator at the metacommunity scale. PMID:22218310

  6. Combined effect of UV-irradiation and TiO?-nanoparticles on the predator-prey interaction of gammarids and mayfly nymphs.

    PubMed

    Kal?íková, Gabriela; Englert, Dominic; Rosenfeldt, Ricki R; Seitz, Frank; Schulz, Ralf; Bundschuh, Mirco

    2014-03-01

    Although nanoparticle production and application increases continuously, their implications in species interactions, especially in combination with other environmental stressors, are rarely assessed. Therefore, the present study investigated the influence of 2 mg/L titanium dioxide nanoparticles (nTiO2; <100 nm) on the interaction between the prey Ephemerella ignita (Ephemeroptera) and the predator Gammarus fossarum (Amphipoda) over 96 h considering UV-irradiation at field relevant levels (approximately 11.4 W/m(2)) as an additional environmental factor (n = 16). At the same time, gammarid's consumption of an alternative food source, i.e. leaf discs, was assessed. All endpoints covered were not affected by nTiO2 alone, while the combination of nTiO2 and UV caused a reduction in gammarid's predation (68%), leaf consumption (60%) and body weight (22%). These effects were most likely triggered by the UV-induced formation of reactive oxygen species by nTiO2. The present study, hence, highlights the importance to cover UV-irradiation during the risk assessment of nanoparticles. PMID:24370671

  7. Emergence of Oscillatory Turing Patterns Induced by Cross Diffusion in a Predator-Prey System

    NASA Astrophysics Data System (ADS)

    Li, An-Wei; Jin, Zhen; Li, Li; Wang, Jian-Zhong

    2012-12-01

    In this paper, we presented a predator-prey model with self diffusion as well as cross diffusion. By using theory on linear stability, we obtain the conditions on Turing instability. The results of numerical simulations reveal that oscillating Turing patterns with hexagons arise in the system. And the values of the parameters we choose for simulations are outside of the Turing domain of the no cross diffusion system. Moreover, we show that cross diffusion has an effect on the persistence of the population, i.e., it causes the population to run a risk of extinction. Particularly, our results show that, without interaction with either a Hopf or a wave instability, the Turing instability together with cross diffusion in a predator-prey model can give rise to spatiotemporally oscillating solutions, which well enrich the finding of pattern formation in ecology.

  8. The interplay between density- and trait-mediated effects in predator-prey interactions: a case study in aphid wing polymorphism.

    PubMed

    Kunert, Grit; Weisser, Wolfgang W

    2003-04-01

    Natural enemies not only influence prey density but they can also cause the modification of traits in their victims. While such non-lethal effects can be very important for the dynamic and structure of prey populations, little is known about their interaction with the density-mediated effects of natural enemies. We investigated the relationship between predation rate, prey density and trait modification in two aphid-aphid predator interactions. Pea aphids (Acyrthosiphon pisum, Harris) have been shown to produce winged dispersal morphs in response to the presence of ladybirds or parasitoid natural enemies. This trait modification influences the ability of aphids to disperse and to colonise new habitats, and hence has a bearing on the population dynamics of the prey. In two experiments we examined wing induction in pea aphids as a function of the rate of predation when hoverfly larvae (Episyrphus balteatus) and lacewing larvae (Chrysoperla carnea) were allowed to forage in pea aphid colonies. Both hoverfly and lacewing larvae caused a significant increase in the percentage of winged morphs among offspring compared to control treatments, emphasising that wing induction in the presence of natural enemies is a general response in pea aphids. The percentage of winged offspring was, however, dependent on the rate of predation, with a small effect of predation on aphid wing induction at very high and very low predation rates, and a strong response of aphids at medium predation rates. Aphid wing induction was influenced by the interplay between predation rate and the resultant prey density. Our results suggests that density-mediated and trait-mediated effects of natural enemies are closely connected to each other and jointly determine the effect of natural enemies on prey population dynamics. PMID:12698353

  9. Testing for predator dependence in predator-prey dynamics: a non-parametric approach.

    PubMed Central

    Jost, C; Ellner, S P

    2000-01-01

    The functional response is a key element in all predator-prey interactions. Although functional responses are traditionally modelled as being a function of prey density only, evidence is accumulating that predator density also has an important effect. However, much of the evidence comes from artificial experimental arenas under conditions not necessarily representative of the natural system, and neglecting the temporal dynamics of the organism (in particular the effects of prey depletion on the estimated functional response). Here we present a method that removes these limitations by reconstructing the functional response non-parametrically from predator-prey time-series data. This method is applied to data on a protozoan predator-prey interaction, and we obtain significant evidence of predator dependence in the functional response. A crucial element in this analysis is to include time-lags in the prey and predator reproduction rates, and we show that these delays improve the fit of the model significantly. Finally, we compare the non-parametrically reconstructed functional response to parametric forms, and suggest that a modified version of the Hassell-Varley predator interference model provides a simple and flexible function for theoretical investigation and applied modelling. PMID:11467423

  10. Quenched Spatial Disorder in Cyclic Three-Species Predator-Prey Models

    NASA Astrophysics Data System (ADS)

    He, Qian; Tauber, Uwe C.

    2011-10-01

    We employ individual-based Monte Carlo simulations to study the effects of quenched spatial disorder in the reaction rates on the co-evolutionary dynamics of cyclic three- species predator-prey models with conserved total particle density. To this end, we numerically explore the oscillatory dynamics of two different variants: (1) the model with symmetric interaction rates near the center of the configuration space, and (2) a strongly asymmetric model version located in one of the three ``corners'' of configuration space. We find that spatial rate variability has only minor effect on the dynamics of generic, not strongly asymmetric systems (variant 1). In stark contrast, spatial disorder can greatly enhance the fitness of both minor species in ``corner'' systems (2). Furthermore, through both mean-field analysis and numerical simulation, we conclude that the evolutionary dynamics of two-species Lotka-Volterra predator- prey models is well approximated by such strongly asymmetric cyclic three-species predator-prey systems. Refs.: Qian He, Mauro Mobilia, and Uwe C. Tauber, Phys. Rev. E 82, 051909 (2010); Qian He and Uwe C.Tauber, in preparation (2011).

  11. Confinement transitions in predator-prey models for tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Dendy, Richard; Zhu, Hao; Chapman, Sandra

    2013-10-01

    Energy transport in tokamak plasmas is mainly determined by small-scale turbulence and larger coherent nonlinear structures, and their interactions. Zero-dimensional models of this offer a simple direct way of capturing the physical origins of enhanced energy confinement and transitions between regimes. The prime zero-dimensional paradigm is predator-prey. We have extended a three-variable (temperature gradient; microturbulence level; one class of coherent structure) model, by adding a fourth variable representing a second class of coherent structure. We investigate the degree of invariance of the phenomenology generated by the two models given this change. We compare the long-time behavior of the systems, their evolution to the final state, and their attractive fixed points and limit cycles. We explore the sensitivity of paths to attractors. Having thus confirmed that the model approach is robust, we investigate transitions to enhanced confinement regimes triggered by sharp changes in external heating, and relate this aspect of model phenomenology to tokamaks.

  12. Relaxation oscillations in a class of predator–prey systems

    Microsoft Academic Search

    Weishi Liu; Dongmei Xiao; Yingfei Yi

    2003-01-01

    We consider a class of three-dimensional, singularly perturbed predator–prey systems having two predators competing exploitatively for the same prey in a constant environment. By using dynamical systems techniques and the geometric singular perturbation theory, we give precise conditions which guarantee the existence of stable relaxation oscillations for systems within the class. Such result shows the coexistence of the predators and

  13. RELAXATION OSCILLATIONS IN A CLASS OF PREDATOR-PREY SYSTEMS

    Microsoft Academic Search

    Weishi Liu

    Abstract. We consider a class of three dimensional, singularly perturbed predator-prey systems having two predators competing exploitatively for the same prey in a constant environment. By using dynamical systems techniques and the geometric singular perturbation theory, we give precise conditions which guarantee the existence of stable relaxation oscillations for systems within the class. Such result shows the coexistence of the

  14. Effects of uniform rotational flow on predator-prey system

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee

    2012-12-01

    Rotational flow is often observed in lotic ecosystems, such as streams and rivers. For example, when an obstacle interrupts water flowing in a stream, energy dissipation and momentum transfer can result in the formation of rotational flow, or a vortex. In this study, I examined how rotational flow affects a predator-prey system by constructing a spatially explicit lattice model consisting of predators, prey, and plants. A predation relationship existed between the species. The species densities in the model were given as S (for predator), P (for prey), and G (for plant). A predator (prey) had a probability of giving birth to an offspring when it ate prey (plant). When a predator or prey was first introduced, or born, its health state was assigned an initial value of 20 that subsequently decreased by one with every time step. The predator (prey) was removed from the system when the health state decreased to less than zero. The degree of flow rotation was characterized by the variable, R. A higher R indicates a higher tendency that predators and prey move along circular paths. Plants were not affected by the flow because they were assumed to be attached to the streambed. Results showed that R positively affected both predator and prey survival, while its effect on plants was negligible. Flow rotation facilitated disturbances in individuals’ movements, which consequently strengthens the predator and prey relationship and prevents death from starvation. An increase in S accelerated the extinction of predators and prey.

  15. Predator interference and stability of predator-prey dynamics.

    PubMed

    P?ibylová, Lenka; Berec, Lud?k

    2015-08-01

    Predator interference, that is, a decline in the per predator consumption rate as predator density increases, is generally thought to promote predator-prey stability. Indeed, this has been demonstrated in many theoretical studies on predator-prey dynamics. In virtually all of these studies, the stabilization role is demonstrated as a weakening of the paradox of enrichment. With predator interference, stable limit cycles that appear as a result of environmental enrichment occur for higher values of the environmental carrying capacity of prey, and even a complete absence of the limit cycles can happen. Here we study predator-prey dynamics using the Rosenzweig-MacArthur-like model in which the Holling type II functional response has been replaced by a predator-dependent family which generalizes many of the commonly used descriptions of predator interference. By means of a bifurcation analysis we show that sufficiently strong predator interference may bring about another stabilizing mechanism. In particular, hysteresis combined with (dis)appearance of stable limit cycles imply abrupt increases in both the prey and predator densities and enhanced persistence and resilience of the predator-prey system. We encourage refitting the previously collected data on predator consumption rates as well as for conducting further predation experiments to see what functional response from the explored family is the most appropriate. PMID:25108420

  16. Predator-Prey Model for Haloes in Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Esposito, L. W.; Bradley, E. T.; Colwell, J. E.; Madhusudhanan, P.; Sremcevic, M.

    2013-09-01

    ISS, VIMS, UVIS spectroscopy and occultations show haloes around the strongest density waves. Based on a predator-prey model for ring dynamics, we offer the following explanation: •Cyclic velocity changes cause the perturbed regions to reach higher collision speeds at some orbital phases, which preferentially removes small regolith particles; •This forms a bright halo around the ILR, if the forcing is strong enough; •Surrounding particles diffuse back too slowly to erase the effect; they diffuse away to form the halo.

  17. Nash Equilibria in Noncooperative Predator-Prey Games

    SciTech Connect

    Ramos, Angel Manuel [Departamento de Matematica Aplicada, Universidad Complutense de Madrid, Plaza de Ciencias 3, 28040 (Spain)], E-mail: Angel_Ramos@mat.ucm.es; Roubicek, Tomas [Mathematical Institute, Charles University, Sokolovska 83, CZ-186 75 Praha 8 and Institute of Information Theory and Automation, Academy of Sciences, Pod vodarenskou vezi 4 (Czech Republic)], E-mail: roubicek@karlin.mff.cuni.cz

    2007-09-15

    A noncooperative game governed by a distributed-parameter predator-prey system is considered, assuming that two players control initial conditions for predator and prey, respectively. Existence of a Nash equilibrium is shown under the condition that the desired population profiles and the environmental carrying capacity for the prey are sufficiently small. A conceptual approximation algorithm is proposed and analyzed. Finally, numerical simulations are performed, too.

  18. The Influence of Predator–Prey Population Dynamics on the Long-term Evolution of Food Web Structure

    Microsoft Academic Search

    BARBARA DROSSEL; PAUL G. HIGGS; ALAN J. MCKANE

    2001-01-01

    We develop a set of equations to describe the population dynamics of many interacting species in food webs. Predator–prey interactions are nonlinear, and are based on ratio-dependent functional responses. The equations account for competition for resources between members of the same species, and between members of different species. Predators divide their total hunting\\/foraging effort between the available prey species according

  19. Impacts of biotic resource enrichment on a predator-prey population.

    PubMed

    Safuan, H M; Sidhu, H S; Jovanoski, Z; Towers, I N

    2013-10-01

    The environmental carrying capacity is usually assumed to be fixed quantity in the classical predator-prey population growth models. However, this assumption is not realistic as the environment generally varies with time. In a bid for greater realism, functional forms of carrying capacities have been widely applied to describe varying environments. Modelling carrying capacity as a state variable serves as another approach to capture the dynamical behavior between population and its environment. The proposed modified predator-prey model is based on the ratio-dependent models that have been utilized in the study of food chains. Using a simple non-linear system, the proposed model can be linked to an intra-guild predation model in which predator and prey share the same resource. Distinct from other models, we formulate the carrying capacity proportional to a biotic resource and both predator and prey species can directly alter the amount of resource available by interacting with it. Bifurcation and numerical analyses are presented to illustrate the system's dynamical behavior. Taking the enrichment parameter of the resource as the bifurcation parameter, a Hopf bifurcation is found for some parameter ranges, which generate solutions that posses limit cycle behavior. PMID:23864218

  20. Simple finite element methods for approximating predator-prey dynamics in two dimensions using MATLAB.

    PubMed

    Garvie, Marcus R; Burkardt, John; Morgan, Jeff

    2015-03-01

    We describe simple finite element schemes for approximating spatially extended predator-prey dynamics with the Holling type II functional response and logistic growth of the prey. The finite element schemes generalize 'Scheme 1' in the paper by Garvie (Bull Math Biol 69(3):931-956, 2007). We present user-friendly, open-source MATLAB code for implementing the finite element methods on arbitrary-shaped two-dimensional domains with Dirichlet, Neumann, Robin, mixed Robin-Neumann, mixed Dirichlet-Neumann, and Periodic boundary conditions. Users can download, edit, and run the codes from http://www.uoguelph.ca/~mgarvie/ . In addition to discussing the well posedness of the model equations, the results of numerical experiments are presented and demonstrate the crucial role that habitat shape, initial data, and the boundary conditions play in determining the spatiotemporal dynamics of predator-prey interactions. As most previous works on this problem have focussed on square domains with standard boundary conditions, our paper makes a significant contribution to the area. PMID:25616741

  1. Computational Science Technical Note CSTN-044 Altruism Amongst Spatial Predator-Prey Animats

    E-print Network

    Hawick, Ken

    0 Computational Science Technical Note CSTN-044 Altruism Amongst Spatial Predator-Prey Animats C. J. Scogings and K. A. Hawick 2008 Understanding the emergence or suppression of altruism is an important step on the part of individual animats. Keywords: altruism, animats, predator-prey BiBTeX reference: @INPROCEEDINGS

  2. Spatial Price Equilibrium and Food Webs: The Economics of Predator-Prey Networks

    E-print Network

    Nagurney, Anna

    Spatial Price Equilibrium and Food Webs: The Economics of Predator-Prey Networks Proceedings and analysis of complex food webs, which are nature's supply chains, through the formalism of network are consumed by predators. Index Terms--spatial price equilibrium, supply chains, food webs, predator prey

  3. Influence of edge on predator prey distribution and abundance

    NASA Astrophysics Data System (ADS)

    Ferguson, Steven H.

    2004-03-01

    I investigated the effect of spatial configuration on distribution and abundance of invertebrate trophic groups by counting soil arthropods under boxes (21 × 9.5 cm) arranged in six different patterns that varied in the amount of edge (137-305 cm). I predicted fewer individuals from the consumer trophic group (Collembola) in box groups with greater amount of edge. This prediction was based on the assumption that predators (mites, ants, spiders, centipedes) select edge during foraging and thereby reduce abundance of the less mobile consumer group under box patterns with greater edge. Consumer abundance (Collembola) was not correlated with amount of edge. Among the predator groups, mite, ant and centipede abundance related to the amount of edge of box groups. However, in contrast to predictions, abundance of these predators was negatively correlated with amount of edge in box patterns. All Collembola predators, with the exception of ants, were less clumped in distribution than Collembola. The results are inconsistent with the view that predators used box edges to predate the less mobile consumer trophic group. Alternative explanations for the spatial patterns other than predator-prey relations include (1) a negative relationship between edge and moisture, (2) a positive relationship between edge and detritus decomposition (i.e. mycelium as food for the consumer group), and (3) a negative relationship between edge and the interstices between adjacent boxes. Landscape patterns likely affect microclimate, food, and predator-prey relations and, therefore, future experimental designs need to control these factors individually to distinguish among alternative hypotheses.

  4. Modeling symbiosis by interactions through species carrying capacities

    NASA Astrophysics Data System (ADS)

    Yukalov, V. I.; Yukalova, E. P.; Sornette, D.

    2012-08-01

    We introduce a mathematical model of symbiosis between different species by taking into account the influence of each species on the carrying capacities of the others. The modeled entities can pertain to biological and ecological societies or to social, economic and financial societies. Our model includes three basic types: symbiosis with direct mutual interactions, symbiosis with asymmetric interactions, and symbiosis without direct interactions. In all cases, we provide a complete classification of all admissible dynamical regimes. The proposed model of symbiosis turned out to be very rich, as it exhibits four qualitatively different regimes: convergence to stationary states, unbounded exponential growth, finite-time singularity, and finite-time death or extinction of species.

  5. Predator-prey pursuit-evasion games in structurally complex environments.

    PubMed

    Morice, Sylvie; Pincebourde, Sylvain; Darboux, Frédéric; Kaiser, Wilfried; Casas, Jérôme

    2013-11-01

    Pursuit and evasion behaviors in many predator-prey encounters occur in a geometrically structured environment. The physical structures in the environment impose strong constraints on the perception and behavioral responses of both antagonists. Nevertheless, no experimental or theoretical study has tackled the issue of quantifying the role of the habitat's architecture on the joint trajectories during a predator-prey encounter. In this study, we report the influence of microtopography of forest leaf litter on the pursuit-evasion trajectories of wolf spiders Pardosa sp. attacking the wood cricket Nemobius sylvestris. Fourteen intact leaf litter samples of 1 m × 0.5 m were extracted from an oak-beech forest floor in summer and winter, with later samples having the most recently fallen leaves. Elevation was mapped at a spatial resolution of 0.5 mm using a laser scanner. Litter structuring patterns were identified by height transects and experimental semi-variograms. Detailed analysis of all visible leaf-fragments of one sample enabled us to relate the observed statistical patterns to the underlying geometry of individual elements. Video recording of pursuit-evasion sequences in arenas with flat paper or leaf litter enabled us to estimate attack and fleeing distances as a function of substrate. The compaction index, the length of contiguous flat surfaces, and the experimental variograms showed that the leaf litter was smoother in summer than in winter. Thus, weathering as well as biotic activities compacted and flattened the litter over time. We found good agreement between the size of the structuring unit of leaf litter and the distance over which attack and escape behaviors both were initiated (both ?3 cm). There was a four-fold topographical effect on pursuit-escape sequences; compared with a flat surface, leaf litter (1) greatly reduced the likelihood of launching a pursuit, (2) reduced pursuit and escape distances by half, (3) put prey and predator on par in terms of pursuit and escape distances, and (4) reduced the likelihood of secondary pursuits, after initial escape of the prey, to nearly zero. Thus, geometry of the habitat strongly modulates the rules of pursuit-evasion in predator-prey interactions in the wild. PMID:23720527

  6. Gause’s principle in interspecific competition of the cyclic predator-prey system

    NASA Astrophysics Data System (ADS)

    Pan, Qiuhui; Wang, Haoying; Chen, Luyi; Huang, Zhong; He, Mingfeng

    2014-02-01

    In this paper, we study the law of survival for species in interspecific competition in the cyclic and predator-prey system. In our model, the successful rate for a predator to prey depends on the individual ability to prey and the two interacting clusters sizes, and the size of a cluster is determined by the aggregation degree between individuals. Experimental results show that only one species can survive when competition occurs on one niche. And which species can survive ultimately depends on the relative relationship between the average individual ability to prey and the aggregation degree between it and its competing species. If competing species have identical values for the average individual ability to prey and the aggregation degree, the species that can survive is determined at random. Therefore, Gause’s Competitive Exclusion Principle is correct, but the causes of competing species to survive are different.

  7. Predator-Prey Dynamics Driven by Feedback between Functionally Diverse Trophic Levels

    PubMed Central

    Wirtz, Kai; Gaedke, Ursula

    2011-01-01

    Neglecting the naturally existing functional diversity of communities and the resulting potential to respond to altered conditions may strongly reduce the realism and predictive power of ecological models. We therefore propose and study a predator-prey model that describes mutual feedback via species shifts in both predator and prey, using a dynamic trait approach. Species compositions of the two trophic levels were described by mean functional traits—prey edibility and predator food-selectivity—and functional diversities by the variances. Altered edibility triggered shifts in food-selectivity so that consumers continuously respond to the present prey composition, and vice versa. This trait-mediated feedback mechanism resulted in a complex dynamic behavior with ongoing oscillations in the mean trait values, reflecting continuous reorganization of the trophic levels. The feedback was only possible if sufficient functional diversity was present in both trophic levels. Functional diversity was internally maintained on the prey level as no niche existed in our system, which was ideal under any composition of the predator level due to the trade-offs between edibility, growth and carrying capacity. The predators were only subject to one trade-off between food-selectivity and grazing ability and in the absence of immigration, one predator type became abundant, i.e., functional diversity declined to zero. In the lack of functional diversity the system showed the same dynamics as conventional models of predator-prey interactions ignoring the potential for shifts in species composition. This way, our study identified the crucial role of trade-offs and their shape in physiological and ecological traits for preserving diversity. PMID:22096560

  8. Foraging and vulnerability traits modify predator-prey body mass allometry: freshwater macroinvertebrates as a case study.

    PubMed

    Klecka, Jan; Boukal, David S

    2013-09-01

    1. Predation is often size selective, but the role of other traits of the prey and predators in their interactions is little known. This hinders our understanding of the causal links between trophic interactions and the structure of animal communities. Better knowledge of trophic traits underlying predator-prey interactions is also needed to improve models attempting to predict food web structure and dynamics from known species traits. 2. We carried out laboratory experiments with common freshwater macroinvertebrate predators (diving beetles, dragonfly and damselfly larvae and water bugs) and their prey to assess how body size and traits related to foraging (microhabitat use, feeding mode and foraging mode) and to prey vulnerability (microhabitat use, activity and escape behaviour) affect predation strength. 3. The underlying predator-prey body mass allometry characterizing mean prey size and total predation pressure was modified by feeding mode of the predators (suctorial or chewing). Suctorial predators fed upon larger prey and had ˜3 times higher mass-specific predation rate than chewing predators of the same size and may thus have stronger effect on prey abundance. 4. Strength of individual trophic links, measured as mortality of the focal prey caused by the focal predator, was determined jointly by the predator and prey body mass and their foraging and vulnerability traits. In addition to the feeding mode, interactions between prey escape behaviour (slow or fast), prey activity (sedentary or active) and predator foraging mode (searching or ambush) strongly affected prey mortality. Searching predators was ineffective in capturing fast-escape prey in comparison with the remaining predator-prey combinations, while ambush predators caused higher mortality than searching predators and the difference was larger in active prey. 5. Our results imply that the inclusion of the commonly available qualitative data on foraging traits of predators and vulnerability traits of prey could substantially increase biological realism of food web descriptions. PMID:23869526

  9. Does Sex-Selective Predation Stabilize or Destabilize Predator-Prey Dynamics?

    Microsoft Academic Search

    David S. Boukal; Ludek Berec; Vlastimil Krivan; Robert Brooks

    2008-01-01

    BackgroundLittle is known about the impact of prey sexual dimorphism on predator-prey dynamics and the impact of sex-selective harvesting and trophy hunting on long-term stability of exploited populations.Methodology and Principal FindingsWe review the quantitative evidence for sex-selective predation and study its long-term consequences using several simple predator-prey models. These models can be also interpreted in terms of feedback between harvesting

  10. Behavioral response races, predator-prey shell games, ecology of fear, and patch use of pumas and their ungulate prey.

    PubMed

    Laundré, John W

    2010-10-01

    The predator-prey shell game predicts random movement of prey across the landscape, whereas the behavioral response race and landscape of fear models predict that there should be a negative relationship between the spatial distribution of a predator and its behaviorally active prey. Additionally, prey have imperfect information on the whereabouts of their predator, which the predator should incorporate in its patch use strategy. I used a one-predator-one-prey system, puma (Puma concolor)-mule deer (Odocoileus hemionus) to test the following predictions regarding predator-prey distribution and patch use by the predator. (1) Pumas will spend more time in high prey risk/low prey use habitat types, while deer will spend their time in low-risk habitats. Pumas should (2) select large forage patches more often, (3) remain in large patches longer, and (4) revisit individual large patches more often than individual smaller ones. I tested these predictions with an extensive telemetry data set collected over 16 years in a study area of patchy forested habitat. When active, pumas spent significantly less time in open areas of low intrinsic predation risk than did deer. Pumas used large patches more than expected, revisited individual large patches significantly more often than smaller ones, and stayed significantly longer in larger patches than in smaller ones. The results supported the prediction of a negative relationship in the spatial distribution of a predator and its prey and indicated that the predator is incorporating the prey's imperfect information about its presence. These results indicate a behavioral complexity on the landscape scale that can have far-reaching impacts on predator-prey interactions. PMID:21058559

  11. Predator-Prey Model for A-Ring Haloes

    NASA Astrophysics Data System (ADS)

    Esposito, L. W.; Madhusudhana, P.; Colwell, J. E.; Sremcevic, M.; Bradley, E. T.

    2013-12-01

    Cassini ISS, VIMS, UVIS spectroscopy and occultations show bright haloes around the strongest density waves. . We observe opposing effects: both small and large particles are found at the perturbed locations. Based on a predator-prey model for ring dynamics, we offer the following explanation: Cyclic velocity changes cause perturbed regions to reach higher collision speeds at some orbital phases, which preferentially removes small regolith particles; This forms a halo around the ILR; Surrounding particles diffuse back too slowly to erase the effect; Meteoritic bombardment creates fresh ice fragments at the regions of decreased regolith. Our explanation is based on the idea that moon-triggered clumping occurs at perturbed regions in Saturn's rings. Cyclic system trajectories forced around the stable point create both high velocity dispersion and large aggregates at these distances. This explanation supports the view of a triple architecture of ring particles: a broad size distribution of particles; that aggregate into temporary rubble piles; coated by a regolith of dust. The aggregate model can explain the dynamic nature of the rings and the aggregates can renew rings by shielding and recycling fresh ice.

  12. Biocontrol in an impulsive predator-prey model.

    PubMed

    Terry, Alan J

    2014-10-01

    We study a model for biological pest control (or "biocontrol") in which a pest population is controlled by a program of periodic releases of a fixed yield of predators that prey on the pest. Releases are represented as impulsive increases in the predator population. Between releases, predator-pest dynamics evolve according to a predator-prey model with some fairly general properties: the pest population grows logistically in the absence of predation; the predator functional response is either of Beddington-DeAngelis type or Holling type II; the predator per capita birth rate is bounded above by a constant multiple of the predator functional response; and the predator per capita death rate is allowed to be decreasing in the predator functional response and increasing in the predator population, though the special case in which it is constant is permitted too. We prove that, when the predator functional response is of Beddington-DeAngelis type and the predators are not sufficiently voracious, then the biocontrol program will fail to reduce the pest population below a particular economic threshold, regardless of the frequency or yield of the releases. We prove also that our model possesses a pest-eradication solution, which is both locally and globally stable provided that predators are sufficiently voracious and that releases occur sufficiently often. We establish, curiously, that the pest-eradication solution can be locally stable whilst not being globally stable, the upshot of which is that, if we delay a biocontrol response to a new pest invasion, then this can change the outcome of the response from pest eradication to pest persistence. Finally, we state a number of specific examples for our model, and, for one of these examples, we corroborate parts of our analysis by numerical simulations. PMID:25195089

  13. Predator-Prey model for haloes in Saturn's A ring

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.; Bradley, E. Todd; Colwell, Joshua E.; Madhusudhanan, Prasanna; Sremcevic, Miodrag

    2013-04-01

    UVIS SOI reflectance spectra show bright 'haloes' around the locations of some of the strongest resonances in Saturn's A ring (Esposito etal 2005). UV spectra constrain the size and composition of the icy ring particles (Bradley etal 2010, 2012). The correspondence of IR, UV spectroscopy, HSP wavelet analysis indicate that we detect the same phenomenon. We investigate the Janus 2:1. 4:3, 5:3, 6:5 and Mimas 5:3 inner Lindblad resonances as well as at the Mimas 5:3 vertical resonance (bending wave location). Models of ring particle regolith evolution (Elliott and Esposito 2010) indicate the deeper regolith is made of older and purer ice. The strong resonances can cause streamline crowding (Lewis and Stewart 2005) which damps the interparticle velocity, allowing temporary clumps to grow, which in turn increase the velocity, eroding the clumps and releasing smaller particles and regolith (see the predator-prey model of Esposito etal 2012). This cyclic behavior, driven by the resonant perturbation from the moon, can yield collision velocities at particular azimuths greater than 1m/sec, sufficient to erode the aggregates (Blum 2006), exposing older, purer materials: In the perturbed region, collisions erode the regolith, removing smaller particles. The released regolith material settles in the less perturbed neighboring regions. Diffusion spreads these ring particles with smaller regolith into a 'halo'. Thus, the radial location of the strongest resonances can be where we find both large aggregates and disrupted fragments, in a balance maintained by the periodic moon forcing. If this stirring exposes older, and purer ice, the velocity threshold for eroding the aggregates can explain why only the strongest Lindblad resonances show haloes. Diffusion can explain the morphology of these haloes, although they are not well-resolved spatially by UVIS.

  14. An experimental analysis of the importance of body-size in the seastar-mussel predator-prey relationship

    NASA Astrophysics Data System (ADS)

    Sommer, Ulrich; Meusel, Bodo; Stielau, Cordula

    1999-04-01

    Laboratory feeding experiments were conducted to elucidate size-relationships in the seastar-mussel ( Asterias rubens-Mytilus edulis) predator-prey interaction. This is one of the most well-known predator-prey relationships in marine benthic ecology and the dependence of seastar feeding rates and prey size selection are crucial for modelling. Moreover, the hypothesis should be tested that large individuals of M. edulis enjoy a size-refuge from seastar predation in the Baltic sea. Ingestion rates showed an allometric relationship to seastar size. They increased slightly more than cubically (b = 3.62) with the linear size of the seastars and slightly more than linearly (b = 1.27) with the body mass of the seastars. Somatic growth rates were linearly related to ingestion rates. Larger seastars tended to eat larger mussels. This relationship was significant for the largest size of mussels eaten and for the mean size of mussels eaten, but not for the minimal size. Size selection of seastars did not depend on the spatial arrangement of mussel sizes relative to the initial position of the seastars in the aquarium. Mussels of > 48 mm in length are safe from predation by the largest seastars found in the western Baltic sea.

  15. Predator-prey trophic relationships in response to organic management practices.

    PubMed

    Schmidt, Jason M; Barney, Sarah K; Williams, Mark A; Bessin, Ricardo T; Coolong, Timothy W; Harwood, James D

    2014-08-01

    A broad range of environmental conditions likely regulate predator-prey population dynamics and impact the structure of these communities. Central to understanding the interplay between predator and prey populations and their importance is characterizing the corresponding trophic interactions. Here, we use a well-documented molecular approach to examine the structure of the community of natural enemies preying upon the squash bug, Anasa tristis, a herbivorous cucurbit pest that severely hinders organic squash and pumpkin production in the United States. Primer pairs were designed to examine the effects of organic management practices on the strength of these trophic connections and link this metric to measures of the arthropod predator complex density and diversity within an experimental open-field context. Replicated plots of butternut squash were randomly assigned to three treatments and were sampled throughout a growing season. Row-cover treatments had significant negative effects on squash bug and predator communities. In total, 640 predators were tested for squash bug molecular gut-content, of which 11% were found to have preyed on squash bugs, but predation varied over the season between predator groups (coccinellids, geocorids, nabids, web-building spiders and hunting spiders). Through the linking of molecular gut-content analysis to changes in diversity and abundance, these data delineate the complexity of interaction pathways on a pest that limits the profitability of organic squash production. PMID:24673741

  16. Predator prey oscillations in a simple cascade model of drift wave turbulence

    SciTech Connect

    Berionni, V.; Guercan, Oe. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)

    2011-11-15

    A reduced three shell limit of a simple cascade model of drift wave turbulence, which emphasizes nonlocal interactions with a large scale mode, is considered. It is shown to describe both the well known predator prey dynamics between the drift waves and zonal flows and to reduce to the standard three wave interaction equations. Here, this model is considered as a dynamical system whose characteristics are investigated. The analytical solutions for the purely nonlinear limit are given in terms of the Jacobi elliptic functions. An approximate analytical solution involving Jacobi elliptic functions and exponential growth is computed using scale separation for the case of unstable solutions that are observed when the energy injection rate is high. The fixed points of the system are determined, and the behavior around these fixed points is studied. The system is shown to display periodic solutions corresponding to limit cycle oscillations, apparently chaotic phase space orbits, as well as unstable solutions that grow slowly while oscillating rapidly. The period doubling route to transition to chaos is examined.

  17. L-shaped prey isocline in the Gause predator-prey experiments with a prey refuge.

    PubMed

    K?ivan, Vlastimil; Priyadarshi, Anupam

    2015-04-01

    Predator and prey isoclines are estimated from data on yeast-protist population dynamics (Gause et al., 1936). Regression analysis shows that the prey isocline is best fitted by an L-shaped function that has a vertical and a horizontal part. The predator isocline is vertical. This shape of isoclines corresponds with the Lotka-Volterra and the Rosenzweig-MacArthur predator-prey models that assume a prey refuge. These results further support the idea that a prey refuge changes the prey isocline of predator-prey models from a horizontal to an L-shaped curve. Such a shape of the prey isocline effectively bounds amplitude of predator-prey oscillations, thus promotes species coexistence. PMID:25644756

  18. Computational Science Technical Note CSTN-015 A Zoology of Emergent Patterns in a Predator-Prey Simulation Model

    E-print Network

    Hawick, Ken

    0 Computational Science Technical Note CSTN-015 A Zoology of Emergent Patterns in a Predator Zoology of Emergent Patterns in a Predator-Prey Simulation Model}, booktitle = {Proceedings of the Sixth CSTN-015 A Zoology of Emergent Patterns in a Predator-Prey Simulation Model K.A. Hawick, H.A. James

  19. Interacting Populations. 2.1 Predator/ Prey models

    E-print Network

    Haas, Ruth

    , the length of a day which has a yearly cycle or the phases of the moon which has a monthly cycle. A function repeats or the number of cycles per unit time. So the phases of the moon has frequency once per 28 days

  20. Taphonomic evidence of a Paleogene mammalian predator–prey interaction

    Microsoft Academic Search

    Katerina Vasileiadou; Jerry J. Hooker; Margaret E. Collinson

    2007-01-01

    A taphonomic study has been undertaken on an assemblage of bones and teeth of Isoptychus sp. and Thalerimys fordi (extinct rodent family Theridomyidae) from a single bed in a coastal plain setting, in the Late Eocene (Priabonian) Osborne Member, Headon Hill Formation (Hampshire Basin, UK). The vertebrate fossils show good preservation and do not bear the marks of obvious long

  1. A size dependent predator-prey interaction: who pursues whom?

    Microsoft Academic Search

    A. M. De Roos; J. A. J. Metz; E. Evers; A. Leipoldt

    1990-01-01

    We investigate the properties of an (age, size) -structured model for a population of Daphnia that feeds on a dynamical algal food source. The stability of the internal equilibrium is studied in detail and combined\\u000a with numerical studies on the dynamics of the model to obtain insight in the relation between individual behaviour and population\\u000a dynamical phenomena. Particularly the change

  2. Novel predator-prey interactions: is resistance futile?

    Microsoft Academic Search

    Jennifer E. Smith; Christopher J. Whelan; Steven J. Taylor; Michael L. Denight; Mike M. Stake

    2007-01-01

    Premise: Prey species may possess inappropriate behavioural, morphological, and\\/or physiological responses to introduced, novel predators. Thus, introduced predators may exert strong selection on prey species. Organisms: Black-capped vireo, Vireo atricapilla, and the fire ant, Solenopsis invicta. Data: Behavioural response of and time-energy budget for parental vireo defence against nest predation by fire ants. Field site: Fort Hood, Texas, an 88,500-hectare

  3. Food-web models that generate constant predator-prey ratios

    Microsoft Academic Search

    S. J. Mithen; J. H. Lawton

    1986-01-01

    An approximately constant ratio of number of predator species\\/number of prey species is observed in several natural communities, although the exact value of the ratio may vary with habitat and the types of organisms in the food web. We test the hypothesis that a constant predator\\/prey ratio can be generated by what Holt (1977) terms ‘apparent competition’ and what Jeffries

  4. Bionomic Exploitation of a Ratio-Dependent Predator-Prey System

    ERIC Educational Resources Information Center

    Maiti, Alakes; Patra, Bibek; Samanta, G. P.

    2008-01-01

    The present article deals with the problem of combined harvesting of a Michaelis-Menten-type ratio-dependent predator-prey system. The problem of determining the optimal harvest policy is solved by invoking Pontryagin's Maximum Principle. Dynamic optimization of the harvest policy is studied by taking the combined harvest effort as a dynamic…

  5. The Subcritical Collapse of Predator Populations in Discrete-Time Predator-Prey Models

    E-print Network

    de Aguiar, Marcus A. M.

    The Subcritical Collapse of Predator Populations in Discrete-Time Predator-Prey Models MICHAEL G,35] pioneered the use of discrete-time host-parasitoid models. They assumed density-independent growth of coexistence as it arises in a discrete-time Lotka-Volterra model. In Sections 4 and 5, we use simple linear

  6. Senses & Sensibility: Predator-Prey Experiments Reveal How Fish Perceive & Respond to Threats

    ERIC Educational Resources Information Center

    Jones, Jason; Holloway, Barbara; Ketcham, Elizabeth; Long, John

    2008-01-01

    The predator-prey relationship is one of the most recognizable and well-studied animal relationships. One of the more striking aspects of this relationship is the differential natural selection pressure placed on predators and their prey. This differential pressure results from differing costs of failure, the so-called life-dinner principle. If a…

  7. A stochastic model for predator-prey systems: basic properties, stability and computer simulation

    Microsoft Academic Search

    M. Abundo; Tor Vergata

    1991-01-01

    A simple stochastic description of a model of a predator-prey system is given. The evolution of the system is described by means of Itô's stochastic differential equations (SDEs), which are the natural stochastic generalization of the Lotka-Volterra deterministic differential equations. Since these SDEs do not satisfy the usual conditions for the existence and uniqueness of the solution, we state a

  8. Multiple dynamics in a single predator-prey system: experimental effects of food quality.

    PubMed

    Nelson, W A; McCauley, E; Wrona, F J

    2001-06-22

    Recent work with the freshwater zooplankton Daphnia has suggested that the quality of its algal prey can have a significant effect on its demographic rates and life-history patterns. Predator-prey theory linking food quantity and food quality predicts that a single system should be able to display two distinct patterns of population dynamics. One pattern is predicted to have high herbivore and low algal biomass dynamics (high HBD), whereas the other is predicted to have low herbivore and high algal biomass dynamics (low HBD). Despite these predictions and the stoichiometric evidence that many phytoplankton communities may have poor access to food of quality, there have been few tests of whether a dynamic predator-prey system can display both of these distinct patterns. Here we report, to the authors' knowledge, the first evidence for two dynamical patterns, as predicted by theory, in a single predator-prey system. We show that the high HBD is a result of food quantity effects and that the low HBD is a result of food quality effects, which are maintained by phosphorus limitation in the predator. These results provide an important link between the known effects of nutrient limitation in herbivores and the significance of prey quality in predator-prey population dynamics in natural zooplankton communities. PMID:11410147

  9. Stabilizing effects in spatial parasitoid–host and predator–prey models: a review

    Microsoft Academic Search

    Cheryl J. Briggs; Martha F. Hoopes

    2004-01-01

    We review the literature on spatial host–parasitoid and predator–prey models. Dispersal on its own is not stabilizing and can destabilize a stable local equilibrium. We identify three mechanisms whereby limited dispersal of hosts and parasitoids combined with other features, such as spatial and temporal heterogeneity, can promote increased persistence and stability. The first mechanism, “statistical stabilization”, is simply the statistical

  10. Predation of Notiophilus (Coleoptera: Carabidae) on Collembola as a Predator-Prey Teaching Model.

    ERIC Educational Resources Information Center

    Higgins, R. C.

    1982-01-01

    The carabid beetle (Notiophilus) preys readily on an easily-cultured collembolan in simple experimental conditions. Some features of this predator-prey system are outlined to emphasize its use in biology instruction. Experiments with another potential collembolan are described in the context of developing the method for more advanced studies.…

  11. The Macaroni Lab: A Directed Inquiry Project on Predator-Prey Relationships.

    ERIC Educational Resources Information Center

    Oyler, Michelle; Rivera, John; Roffol, Melanie; Gibson, David J.; Middleton, Beth A.; Mathis, Marilyn

    1999-01-01

    Presents a directed-inquiry activity to take students one step beyond observation of how living organisms capture prey. Uses a field lab based upon predator-prey relationships to enliven the teaching of food web concepts to non-science-major freshman undergraduates. Can also be used in teaching high school biology students through college science…

  12. Dynamics of a Ivlev-type predator–prey system with constant rate harvesting

    Microsoft Academic Search

    Li Ling; Weiming Wang

    2009-01-01

    In this paper, by using the analysis of qualitative method and bifurcation theory, we investigate the dynamical properties of the Ivlev-type predator–prey model with nonzero constant prey harvesting and with or without time delay, respectively. It is shown that the system we considered can exhibit the subcritical and supercritical Hopf bifurcation. We also study the effect of the time delay

  13. Random dispersal in a predator-prey-parasite model 1 Introduction

    E-print Network

    Baglama, James

    Random dispersal in a predator-prey-parasite model Abstract. 1 Introduction An intermediate host is a host that harbors the parasite only for a short transition period of time, during which some developmental stage may be completed. On the other hand, a definitive host is a host in which the parasite

  14. Effect of a protection zone in the diffusive Leslie predator-prey model

    NASA Astrophysics Data System (ADS)

    Du, Yihong; Peng, Rui; Wang, Mingxin

    In this paper, we consider the diffusive Leslie predator-prey model with large intrinsic predator growth rate, and investigate the change of behavior of the model when a simple protection zone ? for the prey is introduced. As in earlier work [Y. Du, J. Shi, A diffusive predator-prey model with a protection zone, J. Differential Equations 229 (2006) 63-91; Y. Du, X. Liang, A diffusive competition model with a protection zone, J. Differential Equations 244 (2008) 61-86] we show the existence of a critical patch size of the protection zone, determined by the first Dirichlet eigenvalue of the Laplacian over ? and the intrinsic growth rate of the prey, so that there is fundamental change of the dynamical behavior of the model only when ? is above the critical patch size. However, our research here reveals significant difference of the model's behavior from the predator-prey model studied in [Y. Du, J. Shi, A diffusive predator-prey model with a protection zone, J. Differential Equations 229 (2006) 63-91] with the same kind of protection zone. We show that the asymptotic profile of the population distribution of the Leslie model is governed by a standard boundary blow-up problem, and classical or degenerate logistic equations.

  15. Spatial Price Equilibrium and Food Webs: The Economics of Predator-Prey Networks

    E-print Network

    Nagurney, Anna

    Spatial Price Equilibrium and Food Webs: The Economics of Predator-Prey Networks Anna Nagurney1 to present this research Anna and Ladimer S. Nagurney Spatial Price Equilibrium and Food Webs #12;Outline and Suggestions for Future Research Anna and Ladimer S. Nagurney Spatial Price Equilibrium and Food Webs #12

  16. The stage-structured predator-prey model and optimal harvesting policy.

    PubMed

    Zhang, X A; Chen, L; Neumann, A U

    2000-12-01

    In this paper, we establish a mathematical model of two species with stage structure and the relation of predator-prey, to obtain the necessary and sufficient condition for the permanence of two species and the extinction of one species or two species. We also obtain the optimal harvesting policy and the threshold of the harvesting for sustainable development. PMID:11121566

  17. Deterministic and Stochastic Analysis of a Prey-Dependent Predator-Prey System

    ERIC Educational Resources Information Center

    Maiti, Alakes; Samanta, G. P.

    2005-01-01

    This paper reports on studies of the deterministic and stochastic behaviours of a predator-prey system with prey-dependent response function. The first part of the paper deals with the deterministic analysis of uniform boundedness, permanence, stability and bifurcation. In the second part the reproductive and mortality factors of the prey and…

  18. PUBLISHED VERSION Robustness of predator-prey models for confinement regime transitions in

    E-print Network

    PUBLISHED VERSION Robustness of predator-prey models for confinement regime transitions in fusion of Contents: http://pop.aip.org/resource/1/PHPAEN/v20/i4 Published by the American Institute of Physics Kingdom (Received 22 January 2013; accepted 22 March 2013; published online 10 April 2013) Energy

  19. Nonlinear predator-prey singularly perturbed Robin Problems for reaction diffusion systems.

    PubMed

    Mo, Jia-qi; Han, Xiang-lin

    2003-01-01

    The nonlinear predator-prey reaction diffusion systems for singularly perturbed Robin Problems are considered. Under suitable conditions, the theory of differential inequalities can be used to study the asymptotic behavior of the solution for initial boundary value problems. PMID:12958707

  20. Form of an evolutionary tradeoff affects eco-evolutionary dynamics in a predator-prey system.

    PubMed

    Kasada, Minoru; Yamamichi, Masato; Yoshida, Takehito

    2014-11-11

    Evolution on a time scale similar to ecological dynamics has been increasingly recognized for the last three decades. Selection mediated by ecological interactions can change heritable phenotypic variation (i.e., evolution), and evolution of traits, in turn, can affect ecological interactions. Hence, ecological and evolutionary dynamics can be tightly linked and important to predict future dynamics, but our understanding of eco-evolutionary dynamics is still in its infancy and there is a significant gap between theoretical predictions and empirical tests. Empirical studies have demonstrated that the presence of genetic variation can dramatically change ecological dynamics, whereas theoretical studies predict that eco-evolutionary dynamics depend on the details of the genetic variation, such as the form of a tradeoff among genotypes, which can be more important than the presence or absence of the genetic variation. Using a predator-prey (rotifer-algal) experimental system in laboratory microcosms, we studied how different forms of a tradeoff between prey defense and growth affect eco-evolutionary dynamics. Our experimental results show for the first time to our knowledge that different forms of the tradeoff produce remarkably divergent eco-evolutionary dynamics, including near fixation, near extinction, and coexistence of algal genotypes, with quantitatively different population dynamics. A mathematical model, parameterized from completely independent experiments, explains the observed dynamics. The results suggest that knowing the details of heritable trait variation and covariation within a population is essential for understanding how evolution and ecology will interact and what form of eco-evolutionary dynamics will result. PMID:25336757

  1. Robustness of predator-prey models for confinement regime transitions in fusion plasmas

    SciTech Connect

    Zhu, H. [Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Chapman, S. C. [Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Department of Mathematics and Statistics, University of Tromso (Norway); Dendy, R. O. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2013-04-15

    Energy transport and confinement in tokamak fusion plasmas is usually determined by the coupled nonlinear interactions of small-scale drift turbulence and larger scale coherent nonlinear structures, such as zonal flows, together with free energy sources such as temperature gradients. Zero-dimensional models, designed to embody plausible physical narratives for these interactions, can help to identify the origin of enhanced energy confinement and of transitions between confinement regimes. A prime zero-dimensional paradigm is predator-prey or Lotka-Volterra. Here, we extend a successful three-variable (temperature gradient; microturbulence level; one class of coherent structure) model in this genre [M. A. Malkov and P. H. Diamond, Phys. Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second class of coherent structure. This requires a fourth coupled nonlinear ordinary differential equation. We investigate the degree of invariance of the phenomenology generated by the model of Malkov and Diamond, given this additional physics. We study and compare the long-time behaviour of the three-equation and four-equation systems, their evolution towards the final state, and their attractive fixed points and limit cycles. We explore the sensitivity of paths to attractors. It is found that, for example, an attractive fixed point of the three-equation system can become a limit cycle of the four-equation system. Addressing these questions which we together refer to as 'robustness' for convenience is particularly important for models which, as here, generate sharp transitions in the values of system variables which may replicate some key features of confinement transitions. Our results help to establish the robustness of the zero-dimensional model approach to capturing observed confinement phenomenology in tokamak fusion plasmas.

  2. Robustness of predator-prey models for confinement regime transitions in fusion plasmas

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Chapman, S. C.; Dendy, R. O.

    2013-04-01

    Energy transport and confinement in tokamak fusion plasmas is usually determined by the coupled nonlinear interactions of small-scale drift turbulence and larger scale coherent nonlinear structures, such as zonal flows, together with free energy sources such as temperature gradients. Zero-dimensional models, designed to embody plausible physical narratives for these interactions, can help to identify the origin of enhanced energy confinement and of transitions between confinement regimes. A prime zero-dimensional paradigm is predator-prey or Lotka-Volterra. Here, we extend a successful three-variable (temperature gradient; microturbulence level; one class of coherent structure) model in this genre [M. A. Malkov and P. H. Diamond, Phys. Plasmas 16, 012504 (2009)], by adding a fourth variable representing a second class of coherent structure. This requires a fourth coupled nonlinear ordinary differential equation. We investigate the degree of invariance of the phenomenology generated by the model of Malkov and Diamond, given this additional physics. We study and compare the long-time behaviour of the three-equation and four-equation systems, their evolution towards the final state, and their attractive fixed points and limit cycles. We explore the sensitivity of paths to attractors. It is found that, for example, an attractive fixed point of the three-equation system can become a limit cycle of the four-equation system. Addressing these questions which we together refer to as "robustness" for convenience is particularly important for models which, as here, generate sharp transitions in the values of system variables which may replicate some key features of confinement transitions. Our results help to establish the robustness of the zero-dimensional model approach to capturing observed confinement phenomenology in tokamak fusion plasmas.

  3. Effects of Optimal Antipredator Behavior of Prey on Predator–Prey Dynamics: The Role of Refuges

    Microsoft Academic Search

    Vlastimil K?ivan

    1998-01-01

    The influence of optimal antipredator behavior of prey on predator–prey dynamics in a two-patch environment is studied. One patch represents an open habitat while the other is a refuge for prey. It is assumed that prey maximize their fitness measured by the instantaneous per capita growth rate. In each patch population dynamics is described by the Lotka–Volterra time continuous model.

  4. Optimal Harvesting in an Age-Structured Predator-Prey Model

    SciTech Connect

    Fister, K. Renee [Department of Mathematics and Statistics, Murray State University, Murray, KY 42071-3341 (United States)], E-mail: renee.fister@murraystate.edu; Lenhart, Suzanne [Department of Mathematics, University of Tennessee, Knoxville, TN 37996-1300 (United States) and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6016 (United States)], E-mail: lenhart@math.utk.edu

    2006-06-15

    We investigate optimal harvesting control in a predator-prey model in which the prey population is represented by a first-order partial differential equation with age-structure and the predator population is represented by an ordinary differential equation in time. The controls are the proportions of the populations to be harvested, and the objective functional represents the profit from harvesting. The existence and uniqueness of the optimal control pair are established.

  5. Dynamics in a ratio-dependent predator–prey model with predator harvesting

    Microsoft Academic Search

    Dongmei Xiao; Wenxia Li; Maoan Han

    2006-01-01

    The objective of this paper is to study systematically the dynamical properties of a ratio-dependent predator–prey model with nonzero constant rate predator harvesting. It is shown that the model has at most two equilibria in the first quadrant and can exhibit numerous kinds of bifurcation phenomena, including the bifurcation of cusp type of codimension 2 (i.e., Bogdanov–Takens bifurcation), the subcritical

  6. The rainbow bridge: Hamiltonian limits and resonance in predator-prey dynamics

    Microsoft Academic Search

    Aaron A. King; William M. Schaffer

    1999-01-01

    .  ?In the presence of seasonal forcing, the intricate topology of non-integrable Hamiltonian predator-prey models is shown to\\u000a exercise profound effects on the dynamics and bifurcation structure of more realistic schemes which do not admit a Hamiltonian\\u000a formulation. The demonstration of this fact is accomplished by writing the more general models as perturbations of a Hamiltonian\\u000a limit, ?, in which are

  7. Density-dependent dispersal and relative dispersal affect the stability of predator–prey metacommunities

    Microsoft Academic Search

    Céline Hauzy; Mathias Gauduchon; Florence D. Hulot; Michel Loreau

    2010-01-01

    Although density-dependent dispersal and relative dispersal (the difference in dispersal rates between species) have been documented in natural systems, their effects on the stability of metacommunities are poorly understood. Here we investigate the effects of intra- and interspecific density-dependent dispersal on the regional stability in a predator–prey metacommunity model. We show that, when the dynamics of the populations reach equilibrium,

  8. Optimal path analysis using a predator-prey neural network model

    Microsoft Academic Search

    Scott M. Huse; GRIFFISS AIR

    1990-01-01

    A neural network research effort is currently underway at Rome Air Development Center, the Intelligence and Reconnaissance Division (RADC\\/IR). Griffiss Air Force Base. The purpose of this research is to solve computationally difficult intelligence exploitation problems that have eluded conventional techniques, e.g., target recognition, battlefield multi-sensor correlation and fusion, and intelligence situation assessment.This paper describes the use of a predator-prey

  9. Effects of the heterogeneous landscape on a predator-prey system

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee

    2010-01-01

    In order to understand how a heterogeneous landscape affects a predator-prey system, a spatially explicit lattice model consisting of predators, prey, grass, and landscape was constructed. The predators and preys randomly move on the lattice space and the grass grows in its neighboring site according to its growth probability. When predators and preys meet at the same site at the same time, a number of prey, equal to the number of predators are eaten. This rule was also applied to the relationship between the prey and grass. The predator (prey) could give birth to an offspring when it ate prey (grass), with a birth probability. When a predator or prey animal was initially introduced, or newly born, its health state was set at a given high value. This health state decreased by one with every time step. When the state of an animal decreased to less than zero, the animal died and was removed from the system. The heterogeneous landscape was characterized by parameter H, which controlled the heterogeneity according to the neutral model. The simulation results showed that H positively or negatively affected a predator’s survival, while its effect on prey and grass was less pronounced. The results can be understood by the disturbance of the balance between the prey and predator densities in the areas where the animals aggregated.

  10. Predator-prey imbalances due to a pesticide: density and applicability timing as determining factors for experimental assessments.

    PubMed

    Gutierrez, María Florencia; Negro, Carlos Leandro

    2014-09-01

    Predator-prey relationships are determining factors in sustaining community structure but xenobiotics, including pesticides, have the potential to alter them, causing imbalances at the ecosystem level. Although invertebrate predation on zooplankton is of high importance in shallow lakes, there is still little information regarding disturbances on this trophic interaction. This work assessed the potential effects of a chlorpyrifos-based pesticide (CLP) on the interaction between prawns Macrobrachium borellii and cladocerans Ceriodaphnia dubia, taking into account prey densities, specific time of exposure and contamination level. The analysis was focused on the specific sensitivity of both species and, especially, on the predation rate of M. borellii on C. dubia. The latter was evaluated through different treatments that combined predator and/or prey exposure to the insecticide, before (lapse of 12 h) or during the interaction. Under low prey density, when prawns were previously exposed to the insecticide, their consumption rate was lower than that of controls. Conversely, when cladocerans or both species were previously exposed, the prawns' feeding rate was higher. Under high prey density, there were no substantial differences among treatments. Comparatively, cladocerans were significantly more consumed when the exposure of both species was performed before rather than during the interaction. From the results obtained, it can be assumed that the trophic interaction under study is sensitive to CLP and that individual density and specific time of exposure are important variables to be considered in similar studies in order to obtain realistic results. PMID:24903805

  11. Stability and Bifurcation in a Predator-Prey Model with Age Structure and Delays

    NASA Astrophysics Data System (ADS)

    Liu, Zhihua; Li, Naiwei

    2015-05-01

    This paper investigates a predator-prey model with age structure and two delays. By formulating the age-structured model with delays as a non-densely defined Cauchy problem and applying the theory of integrated semigroup and recently established Hopf bifurcation theory for abstract Cauchy problems with non-dense domain, we show that Hopf bifurcation occurs in the model. This also shows the sensitivity of the model dynamics on the threshold ? which might be taken as a measure of a biological maturation period and a time lag between conception and birth. Numerical simulations are performed to illustrate the obtained results and a summary is given.

  12. Dynamics of a Diffusive Predator-Prey Model with General Nonlinear Functional Response

    PubMed Central

    2014-01-01

    We study a diffusive predator-prey model with nonconstant death rate and general nonlinear functional response. Firstly, stability analysis of the equilibrium for reduced ODE system is discussed. Secondly, sufficient and necessary conditions which guarantee the predator and the prey species to be permanent are obtained. Furthermore, sufficient conditions for the global asymptotical stability of the unique positive equilibrium of the system are derived by using the method of Lyapunov function. Finally, we show that there are no nontrivial steady state solutions for certain parameter configuration. PMID:24688422

  13. Global behaviour of a predator-prey like model with piecewise constant arguments.

    PubMed

    Kartal, Senol; Gurcan, Fuat

    2015-12-01

    The present study deals with the analysis of a predator-prey like model consisting of system of differential equations with piecewise constant arguments. A solution of the system with piecewise constant arguments leads to a system of difference equations which is examined to study boundedness, local and global asymptotic behaviour of the positive solutions. Using Schur-Cohn criterion and a Lyapunov function, we derive sufficient conditions under which the positive equilibrium point is local and global asymptotically stable. Moreover, we show numerically that periodic solutions arise as a consequence of Neimark-Sacker bifurcation of a limit cycle. PMID:26040292

  14. Dynamics of an impulsively controlled Michaelis-Menten type predator-prey system

    NASA Astrophysics Data System (ADS)

    Baek, Hunki; Lim, Yongdo

    2011-04-01

    We study a predator-prey system with a Michaelis-Menten functional response and impulsive perturbations which contain chemical and biological control terms. By applying the Floquet theory, we establish conditions for the existence and stability of prey-free solutions of the system. We also show the existence of a positive periodic solution of the system by using the bifurcation theorem and find a sufficient condition that makes the system permanent. Moreover, numerical results on impulsive perturbations show that the system we consider can give birth to various kinds of dynamical behaviors.

  15. Body masses, functional responses and predator-prey stability.

    PubMed

    Kalinkat, Gregor; Schneider, Florian D; Digel, Christoph; Guill, Christian; Rall, Björn C; Brose, Ulrich

    2013-09-01

    The stability of ecological communities depends strongly on quantitative characteristics of population interactions (type-II vs. type-III functional responses) and the distribution of body masses across species. Until now, these two aspects have almost exclusively been treated separately leaving a substantial gap in our general understanding of food webs. We analysed a large data set of arthropod feeding rates and found that all functional-response parameters depend on the body masses of predator and prey. Thus, we propose generalised functional responses which predict gradual shifts from type-II predation of small predators on equally sized prey to type-III functional-responses of large predators on small prey. Models including these generalised functional responses predict population dynamics and persistence only depending on predator and prey body masses, and we show that these predictions are strongly supported by empirical data on forest soil food webs. These results help unravelling systematic relationships between quantitative population interactions and large-scale community patterns. PMID:23819684

  16. Complex dynamics in a singular Leslie-Gower predator-prey bioeconomic model with time delay and stochastic fluctuations

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Zhang, Qingling; Yan, Xing-Gang

    2014-06-01

    In this paper, a class of singular Leslie-Gower predator-prey bioeconomic models with environment fluctuations and time delays is investigated. Local stability analysis of the model reveals that there is a phenomenon of singularity induced bifurcation due to variation of economic interest of harvesting. By choosing the delay as a bifurcation parameter, it is shown that the Hopf bifurcations can occur as the delay crosses some critical values. Then, the effect of a fluctuating environment on the singular stochastic delayed predator-prey bioeconomic model is discussed. Finally numerical simulations demonstrate that the amplitude of oscillation for population is enhanced when compared with the oscillation observed in the deterministic environment.

  17. Bifurcation and chaos in a discrete-time predator-prey system of Holling and Leslie type

    NASA Astrophysics Data System (ADS)

    Hu, Dongpo; Cao, Hongjun

    2015-05-01

    A discrete-time predator-prey system of Holling and Leslie type with a constant-yield prey harvesting obtained by the forward Euler scheme is studied in detail. The conditions of existence for flip bifurcation and Hopf bifurcation are derived by using the center manifold theorem and bifurcation theory. Numerical simulations including bifurcation diagrams, maximum Lyapunov exponents, phase portraits display new and rich nonlinear dynamical behaviors. More specifically, when the integral step size is chosen as a bifurcation parameter, this paper presents the finding of period- 1, 2, 11, 17, 19, 22 orbits, attracting invariant cycles, and chaotic attractors of the discrete-time predator-prey system of Holling and Leslie type with a constant-yield prey harvesting. These results demonstrate that the integral step size plays a vital role to the local and global stability of the discrete-time predator-prey system with the Holling and Leslie type after the original continuous-time predator-prey system is discretized.

  18. Consequences of double Allee effect on the number of limit cycles in a predator–prey model

    Microsoft Academic Search

    Eduardo González-Olivares; Betsabé González-Yañez; Jaime Mena Lorca; Alejandro Rojas-Palma; José D. Flores

    2011-01-01

    The main goal of this work is to show a comparative analysis of simple continuous time predator–prey models considering the Allee effect affecting the prey population, also known as depensation in fisheries sciences.This phenomenon may be expressed by different mathematical forms, yielding a distinct number of limit cycles surrounding a positive equilibrium point, when two of these different formalizations are

  19. The scaling of locomotor performance in predator-prey encounters: from fish to killer whales.

    PubMed

    Domenici, P

    2001-12-01

    During predator-prey encounters, a high locomotor performance in unsteady manoeuvres (i.e. acceleration, turning) is desirable for both predators and prey. While speed increases with size in fish and other aquatic vertebrates in continuous swimming, the speed achieved within a given time, a relevant parameter in predator-prey encounters, is size independent. In addition, most parameters indicating high performance in unsteady swimming decrease with size. Both theoretical considerations and data on acceleration suggest a decrease with body size. Small turning radii and high turning rates are indices of maneuverability in space and in time, respectively. Maneuverability decreases with body length, as minimum turning radii and maximum turning rates increase and decrease with body length, respectively. In addition, the scaling of linear performance in fish locomotion may be modulated by turning behaviour, which is an essential component of the escape response. In angelfish, for example, the speed of large fish is inversely related to their turning angle, i.e. fish escaping at large turning angles show lower speed than fish escaping at small turning angles. The scaling of unsteady locomotor performance makes it difficult for large aquatic vertebrates to capture elusive prey by using whole-body attacks, since the overall maneuverability and acceleration of small prey is likely to be superior to that of large predators. Feeding strategies in vertebrate predators can be related to the predator-prey length ratios. At prey-predator ratios higher than approximately 10(-2), vertebrate predators are particulate feeders, while at smaller ratios, they tend to be filter feeders. At intermediate ratios, large aquatic predators may use a variety of feeding methods that aid, or do not involve, whole body attacks. Among these are bubble curtains used by humpback whales to trap fish schools, and tail-slapping of fish by delphinids. Tail slapping by killer whales is discussed as an example of these strategies. The speed and acceleration achieved by the flukes of killer whales during tail slaps are higher and comparable, respectively, to those that can be expected in their prey, making tail-slapping an effective predator behaviour. PMID:11733175

  20. Oscillations for a delayed predator-prey model with Hassell-Varley-type functional response.

    PubMed

    Xu, Changjin; Li, Peiluan

    2015-04-01

    In this paper, a delayed predator-prey model with Hassell-Varley-type functional response is investigated. By choosing the delay as a bifurcation parameter and analyzing the locations on the complex plane of the roots of the associated characteristic equation, the existence of a bifurcation parameter point is determined. It is found that a Hopf bifurcation occurs when the parameter ? passes through a series of critical values. The direction and the stability of Hopf bifurcation periodic solutions are determined by using the normal form theory and the center manifold theorem due to Faria and Maglhalaes (1995). In addition, using a global Hopf bifurcation result of Wu (1998) for functional differential equations, we show the global existence of periodic solutions. Some numerical simulations are presented to substantiate the analytical results. Finally, some biological explanations and the main conclusions are included. PMID:25836016

  1. Integrated Pest Management in a Predator-Prey System with Allee Effects.

    PubMed

    Costa, M I S; Dos Anjos, L

    2015-08-01

    A commonly used biocontrol strategy to control invasive pests with Allee effects consists of the deliberate introduction of natural enemies. To enhance the effectiveness of this strategy, several tactics of control of invasive species (e.g., mass-trapping, manual removal of individuals, and pesticide spraying) are combined so as to impair pest outbreaks. This combination of strategies to control pest species dynamics are usually named integrated pest management (IPM). In this work, we devise a predator-prey dynamical model in order to assess the influence of the intensity of chemical killing on the success of an IPM. The biological and mathematical framework presented in this study can also be analyzed in the light of species conservation and food web dynamics theory. PMID:26045054

  2. Dynamics of a predator-prey model with Allee effect and prey group defense

    NASA Astrophysics Data System (ADS)

    Saleh, Khairul

    2015-02-01

    Dynamical properties of a Gauss type of planar predator-prey system with Allee effect and non-monotonic response function are discussed. We are interested in persistent features lying in the first quadrant, which amount to structurally stable phase portraits. We show that all positive solutions are uniformly bounded. It is also proved that the system has at most two equilibria in the interior of the first quadrant and can exhibit interesting bifurcation phenomena, including Bogdanov-Takens, Hopf, transcritical and saddle-node bifurcations. The system may have a stable periodic orbit, or a homoclinic loop, or a heteroclinic connection, a saddle point, or a stable focus, depending on parameter values. Biologically, both populations may survive for certain values of parameters. Computer simulations are also given in support of the conclusions.

  3. Enhanced understanding of predator-prey relationships using molecular methods to identify predator species, individual and sex.

    PubMed

    Mumma, Matthew A; Soulliere, Colleen E; Mahoney, Shane P; Waits, Lisette P

    2014-01-01

    Predator species identification is an important step in understanding predator-prey interactions, but predator identifications using kill site observations are often unreliable. We used molecular tools to analyse predator saliva, scat and hair from caribou calf kills in Newfoundland, Canada to identify the predator species, individual and sex. We sampled DNA from 32 carcasses using cotton swabs to collect predator saliva. We used fragment length analysis and sequencing of mitochondrial DNA to distinguish between coyote, black bear, Canada lynx and red fox and used nuclear DNA microsatellite analysis to identify individuals. We compared predator species detected using molecular tools to those assigned via field observations at each kill. We identified a predator species at 94% of carcasses using molecular methods, while observational methods assigned a predator species to 62.5% of kills. Molecular methods attributed 66.7% of kills to coyote and 33.3% to black bear, while observations assigned 40%, 45%, 10% and 5% to coyote, bear, lynx and fox, respectively. Individual identification was successful at 70% of kills where a predator species was identified. Only one individual was identified at each kill, but some individuals were found at multiple kills. Predator sex was predominantly male. We demonstrate the first large-scale evaluation of predator species, individual and sex identification using molecular techniques to extract DNA from swabs of wild prey carcasses. Our results indicate that kill site swabs (i) can be highly successful in identifying the predator species and individual responsible; and (ii) serve to inform and complement traditional methods. PMID:23957886

  4. A comparison of the seasonal movements of tiger sharks and green turtles provides insight into their predator-prey relationship.

    PubMed

    Fitzpatrick, Richard; Thums, Michele; Bell, Ian; Meekan, Mark G; Stevens, John D; Barnett, Adam

    2012-01-01

    During the reproductive season, sea turtles use a restricted area in the vicinity of their nesting beaches, making them vulnerable to predation. At Raine Island (Australia), the highest density green turtle Chelonia mydas rookery in the world, tiger sharks Galeocerdo cuvier have been observed to feed on green turtles, and it has been suggested that they may specialise on such air-breathing prey. However there is little information with which to examine this hypothesis. We compared the spatial and temporal components of movement behaviour of these two potentially interacting species in order to provide insight into the predator-prey relationship. Specifically, we tested the hypothesis that tiger shark movements are more concentrated at Raine Island during the green turtle nesting season than outside the turtle nesting season when turtles are not concentrated at Raine Island. Turtles showed area-restricted search behaviour around Raine Island for ?3-4 months during the nesting period (November-February). This was followed by direct movement (transit) to putative foraging grounds mostly in the Torres Straight where they switched to area-restricted search mode again, and remained resident for the remainder of the deployment (53-304 days). In contrast, tiger sharks displayed high spatial and temporal variation in movement behaviour which was not closely linked to the movement behaviour of green turtles or recognised turtle foraging grounds. On average, tiger sharks were concentrated around Raine Island throughout the year. While information on diet is required to determine whether tiger sharks are turtle specialists our results support the hypothesis that they target this predictable and plentiful prey during turtle nesting season, but they might not focus on this less predictable food source outside the nesting season. PMID:23284819

  5. ARTICLE IN PRESS Interactions between ectomycorrhizal symbiosis and uorescent

    E-print Network

    Thioulouse, Jean

    of the ectomycorrhizal symbiosis between an Australian Acacia (A. holosericea) and Pisolithus sp. strain IR100. Keywords: Fluorescent pseudomonads; Restriction fragment length polymorphism; Siderotyping; Pisolithus sp- mis) was enhanced when they were inoculated with di¡er- ent strains of Pisolithus spp. or rhizobial

  6. Plant strategies of manipulating predatorprey interactions through allelochemicals: Prospects for application in pest control

    Microsoft Academic Search

    Marcel Dicke; Maurice W. Sabelis; Junji Takabayashi; Jan Bruin; Maarten A. Posthumus

    1990-01-01

    To understand the role of allelochemicals in predator-prey interactions it is not sufficient to study the behavioral responses of predator and prey. One should elucidate the origin of the allelochemicals and be aware that it may be located at another trophic level. These aspects are reviewed for predator-prey interactions in general and illustrated in detail for interactions between predatory mites

  7. Differential effects of mercury on activity and swimming endurance in a model aquatic predator-prey system

    SciTech Connect

    Benton, M.J.; Carlson, J.K.; Benson, W.H. [Univ. of Mississippi, University, MS (United States)

    1994-12-31

    In addition to direct effects of contaminants on organisms, populations and communities, there may also be indirect or secondary effects related to altered behavior. This study examined the effects of mercury exposure on locomotory behavior in a model predator-prey system of largemouth bass (Micropterus salmoides) and fathead minnows (Pimephales promelas). At both low and high mercury concentrations, there was a significant effect of exposure on unforced activity and swimming endurance in fathead minnows. At all tested mercury concentrations, activity and endurance also were both positively correlated to body length. However, largemouth bass unforced activity and swimming endurance were not affected by exposure to low mercury concentrations. In light of these differential locomotory effects at environmentally relevant mercury concentrations, the potential impact on aquatic predator-prey systems will be discussed.

  8. Partial characterization of the global dynamic of a predator-prey model with non constant mortality rate

    Microsoft Academic Search

    Cosme Duque; Marcos Lizana

    2009-01-01

    In this paper we characterize partially the global dynamic of a predator prey model with non constant mortality rate. Concretely,\\u000a we give necessary and sufficient conditions in order the system be dissipative and permanent. We study the global stability\\u000a of the nontrivial equilibrium, when it is unique. We show that it is possible the existence of a unique periodic solution

  9. Dynamical complexities in the Leslie–Gower predator–prey model as consequences of the Allee effect on prey

    Microsoft Academic Search

    Eduardo González-Olivares; Jaime Mena-Lorca; Alejandro Rojas-Palma; José D. Flores

    2011-01-01

    This work deals with the analysis of a predator–prey model derived from the Leslie–Gower type model, where the most common mathematical form to express the Allee effect in the prey growth function is considered.It is well-known that the Leslie–Gower model has a unique globally asymptotically stable equilibrium point. However, it is shown here the Allee effect significantly modifies the original

  10. Absence of Frequent Herpesvirus Transmission in a Nonhuman Primate Predator-Prey System in the Wild

    PubMed Central

    Murthy, Sripriya; Couacy-Hymann, Emmanuel; Metzger, Sonja; Nowak, Kathrin; De Nys, Helene; Boesch, Christophe; Wittig, Roman; Jarvis, Michael A.; Leendertz, Fabian H.

    2013-01-01

    Emergence of viruses into the human population by transmission from nonhuman primates (NHPs) represents a serious potential threat to human health that is primarily associated with the increased bushmeat trade. Transmission of RNA viruses across primate species appears to be relatively frequent. In contrast, DNA viruses appear to be largely host specific, suggesting low transmission potential. Herein, we use a primate predator-prey system to study the risk of herpesvirus transmission between different primate species in the wild. The system was comprised of western chimpanzees (Pan troglodytes verus) and their primary (western red colobus, Piliocolobus badius badius) and secondary (black-and-white colobus, Colobus polykomos) prey monkey species. NHP species were frequently observed to be coinfected with multiple beta- and gammaherpesviruses (including new cytomegalo- and rhadinoviruses). However, despite frequent exposure of chimpanzees to blood, organs, and bones of their herpesvirus-infected monkey prey, there was no evidence for cross-species herpesvirus transmission. These findings suggest that interspecies transmission of NHP beta- and gammaherpesviruses is, at most, a rare event in the wild. PMID:23885068

  11. Population-level consequences of heterospecific density-dependent movements in predator-prey systems.

    PubMed

    Sjödin, Henrik; Brännström, Ke; Söderquist, Mårten; Englund, Göran

    2014-02-01

    In this paper we elucidate how small-scale movements, such as those associated with searching for food and avoiding predators, affect the stability of predator-prey dynamics. We investigate an individual-based Lotka-Volterra model with density-dependent movement, in which the predator and prey populations live in a very large number of coupled patches. The rates at which individuals leave patches depend on the local densities of heterospecifics, giving rise to one reaction norm for each of the two species. Movement rates are assumed to be much faster than demographics rates. A spatial structure of predators and prey emerges which affects the global population dynamics. We derive a criterion which reveals how demographic stability depends on the relationships between the per capita covariance and densities of predators and prey. Specifically, we establish that a positive relationship with prey density and a negative relationship with predator density tend to be stabilizing. On a more mechanistic level we show how these relationships are linked to the movement reaction norms of predators and prey. Numerical results show that these findings hold both for local and global movements, i.e., both when migration is biased towards neighbouring patches and when all patches are reached with equal probability. PMID:24060621

  12. Shedding light on microbial predator-prey population dynamics using a quantitative bioluminescence assay.

    PubMed

    Im, Hansol; Kim, Dasol; Ghim, Cheol-Min; Mitchell, Robert J

    2014-01-01

    This study assessed the dynamics of predation by Bdellovibrio bacteriovorus HD 100. Predation tests with two different bioluminescent strains of Escherichia coli, one expressing a heat-labile bacterial luciferase and the other a heat-stable form, showed near identical losses from both, indicating that protein expression and stability are not responsible for the "shutting-off" of the prey bioluminescence (BL). Furthermore, it was found that the loss in the prey BL was not proportional with the predator-to-prey ratio (PPR), with significantly greater losses seen as this value was increased. This suggests that other factors also play a role in lowering the prey BL. The loss in BL, however, was very consistent within nine independent experiments to the point that we were able to reliably estimate the predator numbers within only 1 h when present at a PPR of 6 or higher, Using a fluorescent prey, we found that premature lysis of the prey occurs at a significant level and was more prominent as the PPR ratio increased. Based upon the supernatant fluorescent signal, even a relatively low PPR of 10-20 led to approximately 5% of the prey population being prematurely lysed within 1 h, while a PPR of 90 led to nearly 15% lysis. Consequently, we developed a modified Lotka-Volterra predator-prey model that accounted for this lysis and is able to reliably estimate the prey and bdelloplast populations for a wide range of PPRs. PMID:24272279

  13. On the selection of ordinary differential equation models with application to predator-prey dynamical models.

    PubMed

    Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

    2015-03-01

    We consider model selection and estimation in a context where there are competing ordinary differential equation (ODE) models, and all the models are special cases of a "full" model. We propose a computationally inexpensive approach that employs statistical estimation of the full model, followed by a combination of a least squares approximation (LSA) and the adaptive Lasso. We show the resulting method, here called the LSA method, to be an (asymptotically) oracle model selection method. The finite sample performance of the proposed LSA method is investigated with Monte Carlo simulations, in which we examine the percentage of selecting true ODE models, the efficiency of the parameter estimation compared to simply using the full and true models, and coverage probabilities of the estimated confidence intervals for ODE parameters, all of which have satisfactory performances. Our method is also demonstrated by selecting the best predator-prey ODE to model a lynx and hare population dynamical system among some well-known and biologically interpretable ODE models. PMID:25287611

  14. Analysis of a Stochastic Predator-Prey Model with Applications to Intrahost HIV Genetic Diversity

    E-print Network

    Leviyang, Sivan

    2009-01-01

    During an infection, HIV experiences strong selection by immune system T cells. Recent experimental work has shown that MHC escape mutations form an important pathway for HIV to avoid such selection. In this paper, we study a model of MHC escape mutation. The model is a predator-prey model with two prey, composed of two HIV variants, and one predator, the immune system CD8 cells. We assume that one HIV variant is visible to CD8 cells and one is not. The model takes the form of a system of stochastic differential equations. Motivated by well-known results concerning the short life-cycle of HIV intrahost, we assume that HIV population dynamics occur on a faster time scale then CD8 population dynamics. This separation of time scales allows us to analyze our model using an asymptotic approach. Using this model we study the impact of an MHC escape mutation on the population dynamics and genetic evolution of the intrahost HIV population. From the perspective of population dynamics, we show that the competition betw...

  15. Density-dependent dispersal and relative dispersal affect the stability of predator-prey metacommunities.

    PubMed

    Hauzy, Céline; Gauduchon, Mathias; Hulot, Florence D; Loreau, Michel

    2010-10-01

    Although density-dependent dispersal and relative dispersal (the difference in dispersal rates between species) have been documented in natural systems, their effects on the stability of metacommunities are poorly understood. Here we investigate the effects of intra- and interspecific density-dependent dispersal on the regional stability in a predator-prey metacommunity model. We show that, when the dynamics of the populations reach equilibrium, the stability of the metacommunity is not affected by density-dependent dispersal. However, the regional stability, measured as the regional variability or the persistence, can be modified by density-dependent dispersal when local populations fluctuate over time. Moreover these effects depend on the relative dispersal of the predator and the prey. Regional stability is modified through changes in spatial synchrony. Interspecific density-dependent dispersal always desynchronizses local dynamics, whereas intraspecific density-dependent dispersal may either synchronize or desynchronize it depending on dispersal rates. Moreover, intra- and interspecific density-dependent dispersal strengthen the top-down control of the prey by the predator at intermediate dispersal rates. As a consequence the regional stability of the metacommunity is increased at intermediate dispersal rates. Our results show that density-dependent dispersal and relative dispersal of species are keys to understanding the response of ecosystems to fragmentation. PMID:20638390

  16. Predator-prey reversal: a possible mechanism for ecosystem hysteresis in the North Sea?

    PubMed

    Fauchald, Per

    2010-08-01

    Removal of large predatory fishes from marine ecosystems has resulted in persistent ecosystem shifts, with collapsed predator populations and super-abundant prey populations. One explanation for these shifts is reversals of predator-prey roles that generate internal feedbacks in the ecosystems. Pelagic forage fish are often predators and competitors to the young life stages of their larger fish predators. I show that cod recruitment in the North Sea has been negatively related to the spawning-stock biomass of herring for the last 44 years. Herring, together with the abundance of Calanus finmarchicus, the major food for cod larvae, were the main predictors of cod recruitment. These predictors were of equivalent importance, worked additively, and explained different parts of the dynamics in cod recruitment. I suggest that intensive harvesting of cod has released herring from predator control, and that a large population of herring suppresses cod recruitment through predation on eggs and larvae. This feedback mechanism can promote alternative stable states and therefore cause hysteresis to occur under changing conditions; however, harvesting of herring might at present prevent a shift in the ecosystem to a herring-dominated state. PMID:20836439

  17. Using predator-prey theory to predict outcomes of broadscale experiments to reduce apparent competition.

    PubMed

    Serrouya, Robert; Wittmann, Meike J; McLellan, Bruce N; Wittmer, Heiko U; Boutin, Stan

    2015-05-01

    Apparent competition is an important process influencing many ecological communities. We used predator-prey theory to predict outcomes of ecosystem experiments aimed at mitigating apparent competition by reducing primary prey. Simulations predicted declines in secondary prey following reductions in primary prey because predators consumed more secondary prey until predator numbers responded to reduced prey densities. Losses were exacerbated by a higher carrying capacity of primary prey and a longer lag time of the predator's numerical response, but a gradual reduction in primary prey was less detrimental to the secondary prey. We compared predictions against two field experiments where endangered woodland caribou (Rangifer tarandus caribou) were victims of apparent competition. First, when deer (Odocoileus sp.) declined suddenly following a severe winter, cougar (Puma concolor) declined with a 1-2-year lag, yet in the interim more caribou were killed by cougars, and caribou populations declined by 40%. Second, when moose (Alces alces) were gradually reduced using a management experiment, wolf (Canis lupus) populations declined but did not shift consumption to caribou, and the largest caribou subpopulation stabilized. The observed contrasting outcomes of sudden versus gradual declines in primary prey supported theoretical predictions. Combining theory with field studies clarified how to manage communities to mitigate endangerment caused by apparent competition that affects many taxa. PMID:25905509

  18. Quasisoliton interaction of pursuitevasion waves in a predatorprey system M. A. Tsyganov

    E-print Network

    Biktashev, Vadim N.

    Quasi­soliton interaction of pursuit­evasion waves in a predator­prey system M. A. Tsyganov differential equations describing two spatially distributed populations in a ``predator­prey'' interaction the gradient of prey (pursuit), negative taxis of prey down the gradient of predators (evasion) and diffusion

  19. Halfsoliton interaction of population taxis waves in predatorprey systems with pursuit and M. A. Tsyganov

    E-print Network

    Biktashev, Vadim N.

    Half­soliton interaction of population taxis waves in predator­prey systems with pursuit type of interaction of waves in a mathe­ matical model of ''prey­predator'' system with taxis, a ``half distributed populations in a ``predator­prey'' relationship with each other, started in our previous works [1

  20. Simulation of Cooperative Behavioral Trends by Local Interaction Rules Osnat Shapira Zinovi Rabinovich Jeffrey S. Rosenschein

    E-print Network

    Rosenschein, Jeff

    older predator-prey experiments (using an evolutionary model [5], designed rules [7], and other approaches [2]), and even including predator-prey experiments with self-motivated agents (e.g., [9Simulation of Cooperative Behavioral Trends by Local Interaction Rules Osnat Shapira Zinovi

  1. Global Hopf Bifurcation on Two-Delays Leslie-Gower Predator-Prey System with a Prey Refuge

    PubMed Central

    Liu, Qingsong; Lin, Yiping; Cao, Jingnan

    2014-01-01

    A modified Leslie-Gower predator-prey system with two delays is investigated. By choosing ?1 and ?2 as bifurcation parameters, we show that the Hopf bifurcations occur when time delay crosses some critical values. Moreover, we derive the equation describing the flow on the center manifold; then we give the formula for determining the direction of the Hopf bifurcation and the stability of bifurcating periodic solutions. Numerical simulations are carried out to illustrate the theoretical results and chaotic behaviors are observed. Finally, using a global Hopf bifurcation theorem for functional differential equations, we show the global existence of the periodic solutions. PMID:24803953

  2. A predator-prey model for moon-triggered clumping in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.; Albers, Nicole; Meinke, Bonnie K.; Srem?evi?, Miodrag; Madhusudhanan, Prasanna; Colwell, Joshua E.; Jerousek, Richard G.

    2012-01-01

    UVIS occultation data show clumping in Saturn's F ring and at the B ring outer edge, indicating aggregation and disaggregation at these locations that are perturbed by Prometheus and by Mimas. The inferred timescales range from hours to months. Occultation profiles of the edge show wide variability, indicating perturbations by local mass aggregations. Structure near the B ring edge is seen in power spectral analysis at scales 200-2000 m. Similar structure is also seen at the strongest density waves, with significance increasing with resonance strength. For the B ring outer edge, the strongest structure is seen at longitudes 90° and 270° relative to Mimas. This indicates a direct relation between the moon and the ring clumping. We propose that the collective behavior of the ring particles resembles a predator-prey system: the mean aggregate size is the prey, which feeds the velocity dispersion; conversely, increasing dispersion breaks up the aggregates. Moons may trigger clumping by streamline crowding, which reduces the relative velocity, leading to more aggregation and more clumping. Disaggregation may follow from disruptive collisions or tidal shedding as the clumps stir the relative velocity. For realistic values of the parameters this yields a limit cycle behavior, as for the ecology of foxes and hares or the "boom-bust" economic cycle. Solving for the long-term behavior of this forced system gives a periodic response at the perturbing frequency, with a phase lag roughly consistent with the UVIS occultation measurements. We conclude that the agitation by the moons in the F ring and at the B ring outer edge drives aggregation and disaggregation in the forcing frame. This agitation of the ring material may also allow fortuitous formation of solid objects from the temporary clumps, via stochastic processes like compaction, adhesion, sintering or reorganization that drives the denser parts of the aggregate to the center or ejects the lighter elements. Any of these more persistent objects would then orbit at the Kepler rate. We would also expect the formation of clumps and some more permanent objects at the other perturbed regions in the rings… including satellite resonances, shepherded ring edges, and near embedded objects like Pan and Daphnis (where the aggregation/disaggregation cycles are forced similar to Prometheus forcing of the F ring).

  3. A multispecies statistical age-structured model to assess predator-prey balance: application to an intensively managed Lake Michigan pelagic fish community

    USGS Publications Warehouse

    Tsehaye, Iyob; Jones, Michael L.; Bence, James R.; Brenden, Travis O.; Madenjian, Charles P.; Warner, David M.

    2014-01-01

    Using a Bayesian model fitting approach, we developed a multispecies statistical catch-at-age model to assess trade-offs between predatory demands and prey productivities, focusing on the Lake Michigan pelagic fish community. We assessed these trade-offs in terms of predation mortalities and productivities of alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) and functional responses of salmonines. Our predation mortality estimates suggest that salmonine consumption has been a major driver of historical fluctuations in prey abundance, with sharp declines in alewife abundance in the 1980s and 2000s coinciding with estimated increases in predation mortalities. While Chinook salmon (Oncorhynchus tshawytscha) were food limited during periods of low alewife abundance, other salmonines appeared to maintain a (near) maximum per-predator consumption across all observed prey densities, suggesting that feedback mechanisms are unlikely to help maintain a balance between predator consumption and prey productivity in Lake Michigan. This study demonstrates that a multispecies modeling approach that combines stock assessment methods with explicit consideration of predator–prey interactions could provide the basis for tactical decision-making from a broader ecosystem perspective.

  4. [Metabolism and interaction of C and N in the arbuscular mycorrhizal symbiosis].

    PubMed

    Li, Yuan-Jing; Liu, Zhi-Lei; He, Xing-Yuan; Tian, Chun-Jie

    2014-03-01

    The arbuscular mycorrhiza (AM) is the symbiont formed by the host plant and the arbuscular mycorrhizal fungi (AMF). The transfer and metabolism of C and N in the symbiosis plays an important role in keeping nutrient balance and resource reallocation between the host plant and the fungi. The carbohydrates produced by plant photosynthesis are transferred to the fungi, where they are metabolized as materials and energy used for fungal spore germination, mycelium growth and uptake of nitrogen and other nutrients. At the same time, N is transferred and reallocated from the fungi to the host plant, where the final released ammonium is used for plant growth. Accordingly, we reviewed the current progress in C and N transfer and metabolism in the AM symbiosis, and the crosstalk between them as well as some key issues to elucidate the mechanism of the interaction between C and N transport in the symbiosis, so as to provide the theory foundation for the application of AM in sustainable agriculture and ecosystem. PMID:24984513

  5. Stream ecological processes are modeled through a simple predator-prey model, which reproduces benthic algae and macro-invertebrates dynamics.

    E-print Network

    reproduces benthic algae and macro-invertebrates dynamics. Algae biomass = growth - death loss - predation loss Macro-invertebrate biomass = growth due to predation - death loss Hydrologic drivers and controls influences on algae and macro-invertebrates dynamics will be introduced in the predator-prey model

  6. Behavioral Interactions Between Aphaenogaster rudis (Hymenoptera: Formicidae) and Reticulitermes flavipes

    E-print Network

    Buczkowski, Grzegorz

    Behavioral Interactions Between Aphaenogaster rudis (Hymenoptera: Formicidae) and Reticulitermes + Business Media, LLC 2008 Abstract Predation pressure from ants is a major driving force in the adaptive to protect themselves against ants. We examined predator­ prey interactions between the woodland ant

  7. Bifurcation analysis and dimension reduction of a predator-prey model for the L-H transition

    SciTech Connect

    Dam, Magnus; Brøns, Morten [Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)] [Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Juul Rasmussen, Jens; Naulin, Volker [Association Euratom-DTU, Department of Physics, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde (Denmark)] [Association Euratom-DTU, Department of Physics, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde (Denmark); Xu, Guosheng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2013-10-15

    The L-H transition denotes a shift to an improved confinement state of a toroidal plasma in a fusion reactor. A model of the L-H transition is required to simulate the time dependence of tokamak discharges that include the L-H transition. A 3-ODE predator-prey type model of the L-H transition is investigated with bifurcation theory of dynamical systems. The analysis shows that the model contains three types of transitions: an oscillating transition, a sharp transition with hysteresis, and a smooth transition. The model is recognized as a slow-fast system. A reduced 2-ODE model consisting of the full model restricted to the flow on the critical manifold is found to contain all the same dynamics as the full model. This means that all the dynamics in the system is essentially 2-dimensional, and a minimal model of the L-H transition could be a 2-ODE model.

  8. A plasma source driven predator-prey like mechanism as a potential cause of spiraling intermittencies in linear plasma devices

    SciTech Connect

    Reiser, D. [Research Center Jülich GmbH, Institute for Energy and Climate Research—Plasma Physics, D-52425 Jülich (Germany)] [Research Center Jülich GmbH, Institute for Energy and Climate Research—Plasma Physics, D-52425 Jülich (Germany); Ohno, N. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)] [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, H. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan); Vela, L. [Physics Department, Universidad Carlos III de Madrid, Avda de la Universidad 30, 28911-Leganés, Madrid (Spain)] [Physics Department, Universidad Carlos III de Madrid, Avda de la Universidad 30, 28911-Leganés, Madrid (Spain)

    2014-03-15

    Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor plasma Simulator-II). The numerical simulations reproduce several features of the intermittent spiraling structures observed, for instance, statistical properties, rotation frequency, and the frequency of plasma expulsion. The detailed inspection of the three-dimensional plasma dynamics allows to identify the key mechanism behind the formation of these intermittent events. The resistive coupling between electron pressure and parallel electric field in the plasma source region gives rise to a quasilinear predator-prey like dynamics where the axisymmetric mode represents the prey and the spiraling structure with low azimuthal mode number represents the predator. This interpretation is confirmed by a reduced one-dimensional quasilinear model derived on the basis of the findings in the full three-dimensional simulations. The dominant dynamics reveals certain similarities to the classical Lotka-Volterra cycle.

  9. Persistence and global stability of Bazykin predator-prey model with Beddington-DeAngelis response function

    NASA Astrophysics Data System (ADS)

    Sarwardi, Sahabuddin; Haque, Mainul; Mandal, Prashanta Kumar

    2014-01-01

    In this article, a predator-prey model of Beddington-DeAngelis type with discrete delay is proposed and analyzed. The essential mathematical features of the proposed model are investigated in terms of local, global analysis and bifurcation theory. By analyzing the associated characteristic equation, it is found that the Hopf bifurcation occurs when the delay parameter ? crosses some critical values. In this article, the classical Bazykin's model is modified with Beddington-DeAngelis functional response. The parametric space under which the system enters into Hopf bifurcation for both delay and non-delay cases are investigated. Global stability results are obtained by constructing suitable Lyapunov functions for both the cases. We also derive the explicit formulae for determining the stability, direction and other properties of bifurcating periodic solutions by using normal form and central manifold theory. Our analytical findings are supported by numerical simulations. Biological implication of the analytical findings are discussed in the conclusion section.

  10. Time-related predator\\/prey interactions between birds and fish in a northern Swedish river

    Microsoft Academic Search

    Kjell SjiJberg

    1989-01-01

    Seasonal and diel activity patterns of mergansers, gulls, and terns along a river in northern Sweden were documented, as were those of their fish prey. The seasonal and diel activity patterns of goosandersMergus merganser and gulls (Larus canus, L. argentatus, andL. fuscus) were closely related to that of the river lampreyLampetra fluviatilis. During the peak spawning of the river lamprey,

  11. Time-related predator/prey interactions between birds and fish in a northern Swedish river.

    PubMed

    Sjöberg, K

    1989-03-01

    Seasonal and diel activity patterns of mergansers, gulls, and terns along a river in northern Sweden were documented, as were those of their fish prey. The seasonal and diel activity patterns of goosandersMergus merganser and gulls (Larus canus, L. argentatus, andL. fuscus) were closely related to that of the river lampreyLampetra fluviatilis. During the peak spawning of the river lamprey, birds showed a nocturnal peak in fishing activity. During the summer solstice, birds were active for 24 h. The activity patterns of red-breasted merganserMergus serrator, ternsSterna spp., and three-spined sticklebacksGasterosteus aculeatus were also similar. Activity pattern of the prey apparently influenced breeding time, diel activity and foraging area of the twoMergus species. Social relations between gulls probably corrdinated their peak in fishing, which coincided with the time lampreys were most efficiently exploited. PMID:23494338

  12. PREDATOR-PREY (VOLE-CRICKET) INTERACTIONS: THE EFFECTS OF WOOD PRESERVATIVES

    EPA Science Inventory

    The rate of loss of crickets (Acheta domestica), with and without the presence of an adventitious predator, the gray-tailed vole (Microtus canicaudus), has been studied in Terrestrial Microcosm Chambers (TMC-II) treated with pine stakes impregnated with creosote, bis(tri-n-butylt...

  13. PREDATOR-PREY INTERACTIONS BETWEEN EAGLES AND CACKLING CANADA AND ROSS' GEESE DURING WINTER IN CALIFORNIA

    Microsoft Academic Search

    SCOTT R. MCWILLIAMS; JON P. DUNN; DENNIS G. RAVELING

    1994-01-01

    Cackling Geese (Brunta canadensis minima) were preyed on heavily in northeastern California by Golden Eagles (Aquila chysaetos) and less commonly by Bald Eagles (Haliaeetus Zeucocephalus) in 19851990. Eagle predation on Cackling Geese was minimal in other wintering locations in California. In the Klamath Basin, eagles killed Cackling Geese most frequently soon (

  14. Generation Time Ratios—Determinants of Prey Abundance in Insect Predator–Prey Interactions

    Microsoft Academic Search

    Pavel Kindlmann; Anthony F. G. Dixon

    1999-01-01

    The potential fitness of an adult insect predator depends mainly on the future trends in resource availability throughout the period of development of its larvae, because they, unlike the adult, are confined to a patch. Thus, adult oviposition strategy is likely to be determined by the bottlenecks in resources that occur during the period of its offsprings' development. Therefore, the

  15. AN IMMUNOLOGICAL TECHNIQUE FOR IDENTIFYING MULTIPLE PREDATOR—PREY INTERACTIONS IN A COMPLEX ARTHROPOD ASSEMBLAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory feeding study was conducted to determine if predation events could be detected from predators that consumed prey marked with foreign protein. In laboratory feeding trials I determined that large and small rabbit immunoglobulin G (IgG) marked prey can be detected by a rabbit IgG-specifi...

  16. Hypoxic refuges, predator-prey interactions and habitat selection by fishes.

    PubMed

    Hedges, K J; Abrahams, M V

    2015-01-01

    Localized hypoxic habitats were created in Delta Marsh, Manitoba, Canada to determine the potential of regions of moderate hypoxia to act as refuges for forage fishes from piscine predators. Minnow traps and giving-up density (GUD) plates (plexiglas plates covered with trout crumble and fine gravel) were used to assess habitat use and perceived habitat quality for forage fishes, respectively, while passive integrated transponder tags provided data on habitat use by predator species to assess the level of predation risk. Data were collected both before and after a hypoxia manipulation (2-3?mg?l(-1) dissolved oxygen, DO) to create a before-after control-effect style experiment. Fathead minnows Pimephales promelas were more abundant and consumed more food from GUD plates in hypoxic bays after the DO manipulation, indicating hypoxic locations were perceived as higher quality, lower-risk habitats. The frequency of predator visits was not consistently affected. The duration of visits, and therefore the total time spent in these habitats, however, was significantly shorter. These predator data, combined with the prey information, are consistent with the hypothesis that hypoxic regions function as predator refuges. The refuge effect is not the result of predator exclusion, however; instead predators are rendered less capable of foraging and pose less of a threat in hypoxic locations. PMID:25557430

  17. Lagrangian studies of animal swimming and aquatic predator-prey interactions

    Microsoft Academic Search

    John Dabiri

    2008-01-01

    Experimental studies of animal swimming have been traditionally based on an Eulerian perspective in which the time-dependent flow field surrounding the animal is measured at fixed locations in space. The measured velocity field and its derivatives (e.g. vorticity) can, in principle, be used to deduce the forces, energetics, and fluid transport associated with locomotion in real fluids. However, achieving a

  18. A finite element model to investigate the predator-prey interaction in the benthic habitat

    Microsoft Academic Search

    A. P. C. Rio; R. C. Almeida

    Many marine organisms release into the ocean planktonic larvae which must reach specific sites in order to recruit to the next stage of their life-cycle. Benthic community structure is affected by pelagic environmental conditions, because these conditions determine the probability that larvae will successfully recruit to the adult habitat (1). In particular for sessile species, the population dynamics are regulated

  19. Evolutionary cycling in predator-prey interactions: population dynamics and the red queen

    Microsoft Academic Search

    Ulf Dieckmann; Paul Marrow; Richard Law

    1995-01-01

    This paper describes the coevolution of phenotypes in a community comprising a population of predators and of prey. It is shown that evolutionary cycling is a likely outcome of the process. The dynamical systems on which this description is based are constructed from microscopic stochastic birth and death events, together with a process of random mutation. Births and deaths are

  20. Predator-prey interactions in the spinifex grasslands of central Australia

    Microsoft Academic Search

    Rachel M Paltridge

    2005-01-01

    Predation by exotic predators (cats Felis catus and foxes Vulpes vulpes) is believed to be one of the factors that has contributed to the decline of medium-sized mammals in arid Australia. Other factors include habitat degradation by introduced herbivores (rabbits Oryctolagus cuniculus and grazing stock) and altered fire regimes after Aboriginal people moved into permanent settlements. In general, the impact

  1. Symbiosis and Pathogenesis: Evolution of the Microbe-Host Interaction

    NASA Astrophysics Data System (ADS)

    Steinert, M.; Hentschel, U.; Hacker, J.

    Symbiotic and pathogenic bacteria have in common that they live in or on host organisms or host cells. To make a successful living in eukaryotic hosts, bacteria must possess the traits to recognize a given host and establish adherence. When the bacterial location is internal or intracellular, they must further have the ability to invade, to establish a niche, and finally to multiply within a host. The underlying mechanisms which allow this form of existence show similarities between symbiotic and pathogenic bacteria. The final outcome, however, may result in a wide spectrum of consequences for the host ranging from the acquisition of novel metabolic pathways to damage or death. Despite the vastly different forms of interactions, symbiotic and pathogenic bacteria have in common that they are adapted to a particular environmental niche represented by the host organism or compartment thereof. This contribution reviews the evolutionary forces which have shaped the microbial-host interactions. Particular emphasis is placed on the genetic and molecular mechanisms that drive bacterial evolution in response to the selective pressures of the host environment.

  2. Multiple stability and uniqueness of the limit cycle in a Gause-type predator–prey model considering the Allee effect on prey

    Microsoft Academic Search

    Eduardo González-Olivares; Héctor Meneses-Alcay; Betsabé González-Yañez; Jaime Mena-Lorca; Alejandro Rojas-Palma; Rodrigo Ramos-Jiliberto

    2011-01-01

    In this work, a bidimensional differential equation system obtained by modifying the well-known predator–prey Rosenzweig–MacArthur model is analyzed by considering prey growth influenced by the Allee effect.One of the main consequences of this modification is a separatrix curve that appears in the phase plane, dividing the behavior of the trajectories. The results show that the equilibrium in the origin is

  3. Multiple Limit Cycles in a Gause Type Predator–Prey Model with Holling Type III Functional Response and Allee Effect on Prey

    Microsoft Academic Search

    Eduardo González-Olivares; Alejandro Rojas-Palma

    2011-01-01

    This work aims to examine the global behavior of a Gause type predator–prey model considering two aspects: (i) the functional\\u000a response is Holling type III and, (ii) the prey growth is affected by the Allee effect. We prove the origin of the system\\u000a is an attractor equilibrium point for all parameter values. It has also been shown that it is

  4. From Cues to Signals: Evolution of Interspecific Communication via Aposematism and Mimicry in a Predator-Prey System

    PubMed Central

    Lehmann, Kenna D. S.; Goldman, Brian W.; Dworkin, Ian; Bryson, David M.; Wagner, Aaron P.

    2014-01-01

    Current theory suggests that many signaling systems evolved from preexisting cues. In aposematic systems, prey warning signals benefit both predator and prey. When the signal is highly beneficial, a third species often evolves to mimic the toxic species, exploiting the signaling system for its own protection. We investigated the evolutionary dynamics of predator cue utilization and prey signaling in a digital predator-prey system in which prey could evolve to alter their appearance to mimic poison-free or poisonous prey. In predators, we observed rapid evolution of cue recognition (i.e. active behavioral responses) when presented with sufficiently poisonous prey. In addition, active signaling (i.e. mimicry) evolved in prey under all conditions that led to cue utilization. Thus we show that despite imperfect and dishonest signaling, given a high cost of consuming poisonous prey, complex systems of interspecific communication can evolve via predator cue recognition and prey signal manipulation. This provides evidence supporting hypotheses that cues may serve as stepping-stones in the evolution of more advanced communication and signaling systems that incorporate information about the environment. PMID:24614755

  5. Food-web structure in relation to environmental gradients and predator-prey ratios in tank-bromeliad ecosystems.

    PubMed

    Dézerald, Olivier; Leroy, Céline; Corbara, Bruno; Carrias, Jean-François; Pélozuelo, Laurent; Dejean, Alain; Céréghino, Régis

    2013-01-01

    Little is known of how linkage patterns between species change along environmental gradients. The small, spatially discrete food webs inhabiting tank-bromeliads provide an excellent opportunity to analyse patterns of community diversity and food-web topology (connectance, linkage density, nestedness) in relation to key environmental variables (habitat size, detrital resource, incident radiation) and predators:prey ratios. We sampled 365 bromeliads in a wide range of understorey environments in French Guiana and used gut contents of invertebrates to draw the corresponding 365 connectance webs. At the bromeliad scale, habitat size (water volume) determined the number of species that constitute food-web nodes, the proportion of predators, and food-web topology. The number of species as well as the proportion of predators within bromeliads declined from open to forested habitats, where the volume of water collected by bromeliads was generally lower because of rainfall interception by the canopy. A core group of microorganisms and generalist detritivores remained relatively constant across environments. This suggests that (i) a highly-connected core ensures food-web stability and key ecosystem functions across environments, and (ii) larger deviations in food-web structures can be expected following disturbance if detritivores share traits that determine responses to environmental changes. While linkage density and nestedness were lower in bromeliads in the forest than in open areas, experiments are needed to confirm a trend for lower food-web stability in the understorey of primary forests. PMID:23977128

  6. Food-Web Structure in Relation to Environmental Gradients and Predator-Prey Ratios in Tank-Bromeliad Ecosystems

    PubMed Central

    Dézerald, Olivier; Leroy, Céline; Corbara, Bruno; Carrias, Jean-François; Pélozuelo, Laurent; Dejean, Alain; Céréghino, Régis

    2013-01-01

    Little is known of how linkage patterns between species change along environmental gradients. The small, spatially discrete food webs inhabiting tank-bromeliads provide an excellent opportunity to analyse patterns of community diversity and food-web topology (connectance, linkage density, nestedness) in relation to key environmental variables (habitat size, detrital resource, incident radiation) and predators:prey ratios. We sampled 365 bromeliads in a wide range of understorey environments in French Guiana and used gut contents of invertebrates to draw the corresponding 365 connectance webs. At the bromeliad scale, habitat size (water volume) determined the number of species that constitute food-web nodes, the proportion of predators, and food-web topology. The number of species as well as the proportion of predators within bromeliads declined from open to forested habitats, where the volume of water collected by bromeliads was generally lower because of rainfall interception by the canopy. A core group of microorganisms and generalist detritivores remained relatively constant across environments. This suggests that (i) a highly-connected core ensures food-web stability and key ecosystem functions across environments, and (ii) larger deviations in food-web structures can be expected following disturbance if detritivores share traits that determine responses to environmental changes. While linkage density and nestedness were lower in bromeliads in the forest than in open areas, experiments are needed to confirm a trend for lower food-web stability in the understorey of primary forests. PMID:23977128

  7. A predator-prey model with a holling type I functional response including a predator mutual interference

    USGS Publications Warehouse

    Seo, G.; DeAngelis, D.L.

    2011-01-01

    The most widely used functional response in describing predator-prey relationships is the Holling type II functional response, where per capita predation is a smooth, increasing, and saturating function of prey density. Beddington and DeAngelis modified the Holling type II response to include interference of predators that increases with predator density. Here we introduce a predator-interference term into a Holling type I functional response. We explain the ecological rationale for the response and note that the phase plane configuration of the predator and prey isoclines differs greatly from that of the Beddington-DeAngelis response; for example, in having three possible interior equilibria rather than one. In fact, this new functional response seems to be quite unique. We used analytical and numerical methods to show that the resulting system shows a much richer dynamical behavior than the Beddington-DeAngelis response, or other typically used functional responses. For example, cyclic-fold, saddle-fold, homoclinic saddle connection, and multiple crossing bifurcations can all occur. We then use a smooth approximation to the Holling type I functional response with predator mutual interference to show that these dynamical properties do not result from the lack of smoothness, but rather from subtle differences in the functional responses. ?? 2011 Springer Science+Business Media, LLC.

  8. Impairment of O-antigen production confers resistance to grazing in a model amoeba–cyanobacterium predator–prey system

    PubMed Central

    Simkovsky, Ryan; Daniels, Emy F.; Tang, Karen; Huynh, Stacey C.; Golden, Susan S.; Brahamsha, Bianca

    2012-01-01

    The grazing activity of predators on photosynthetic organisms is a major mechanism of mortality and population restructuring in natural environments. Grazing is also one of the primary difficulties in growing cyanobacteria and other microalgae in large, open ponds for the production of biofuels, as contaminants destroy valuable biomass and prevent stable, continuous production of biofuel crops. To address this problem, we have isolated a heterolobosean amoeba, HGG1, that grazes upon unicellular and filamentous freshwater cyanobacterial species. We have established a model predator–prey system using this amoeba and Synechococcus elongatus PCC 7942. Application of amoebae to a library of mutants of S. elongatus led to the identification of a grazer-resistant knockout mutant of the wzm ABC O-antigen transporter gene, SynPCC7942_1126. Mutations in three other genes involved in O-antigen synthesis and transport also prevented the expression of O-antigen and conferred resistance to HGG1. Complementation of these rough mutants returned O-antigen expression and susceptibility to amoebae. Rough mutants are easily identifiable by appearance, are capable of autoflocculation, and do not display growth defects under standard laboratory growth conditions, all of which are desired traits for a biofuel production strain. Thus, preventing the production of O-antigen is a pathway for producing resistance to grazing by certain amoebae. PMID:23012457

  9. Consequences of a refuge for the predator-prey dynamics of a wolf-elk system in Banff National Park, Alberta, Canada.

    PubMed

    Goldberg, Joshua F; Hebblewhite, Mark; Bardsley, John

    2014-01-01

    Refugia can affect predator-prey dynamics via movements between refuge and non-refuge areas. We examine the influence of a refuge on population dynamics in a large mammal predator-prey system. Wolves (Canis lupus) have recolonized much of their former range in North America, and as a result, ungulate prey have exploited refugia to reduce predation risk with unknown impacts on wolf-prey dynamics. We examined the influence of a refuge on elk (Cervus elaphus) and wolf population dynamics in Banff National Park. Elk occupy the Banff townsite with little predation, whereas elk in the adjoining Bow Valley experience higher wolf predation. The Banff refuge may influence Bow Valley predator-prey dynamics through source-sink movements. To test this hypothesis, we used 26 years of wolf and elk population counts and the Delayed Rejection Adaptive Metropolis Markov chain Monte Carlo method to fit five predator-prey models: 1) with no source-sink movements, 2) with elk density-dependent dispersal from the refuge to the non-refuge, 3) with elk predation risk avoidance movements from the non-refuge to the refuge, 4) with differential movement rates between refuge and non-refuge, and 5) with short-term, source-sink wolf movements. Model 1 provided the best fit of the data, as measured by Akaike Information Criterion (AIC). In the top model, Banff and Bow Valley elk had median growth rates of 0.08 and 0.03 (95% credibility intervals [CIs]: 0.027-0.186 and 0.001-0.143), respectively, Banff had a median carrying capacity of 630 elk (95% CI: 471.9-2676.9), Bow Valley elk had a median wolf encounter rate of 0.02 (95% CI: 0.013-0.030), and wolves had a median death rate of 0.23 (95% CI: 0.146-0.335) and a median conversion efficiency of 0.07 (95% CI: 0.031-0.124). We found little evidence for potential source-sink movements influencing the predator-prey dynamics of this system. This result suggests that the refuge was isolated from the non-refuge. PMID:24670632

  10. Man-Computer Symbiosis Through Interactive Graphics: A Survey and Identification of Critical Research Areas.

    ERIC Educational Resources Information Center

    Knoop, Patricia A.

    The purpose of this report was to determine the research areas that appear most critical to achieving man-computer symbiosis. An operational definition of man-computer symbiosis was developed by: (1) reviewing and summarizing what others have said about it, and (2) attempting to distinguish it from other types of man-computer relationships. From…

  11. Network structure, predator–prey modules, and stability in large food webs

    Microsoft Academic Search

    Stefano Allesina; Mercedes Pascual

    2008-01-01

    Large, complex networks of ecological interactions with random structure tend invariably to instability. This mathematical\\u000a relationship between complexity and local stability ignited a debate that has populated ecological literature for more than\\u000a three decades. Here we show that, when species interact as predators and prey, systems as complex as the ones observed in\\u000a nature can still be stable. Moreover, stability

  12. Crossing the hopf bifurcation in a live predator-prey system.

    PubMed

    Fussmann, G F; Ellner, S P; Shertzer, K W; Hairston, N G

    2000-11-17

    Population biologists have long been interested in the oscillations in population size displayed by many organisms in the field and laboratory. A wide range of deterministic mathematical models predict that these fluctuations can be generated internally by nonlinear interactions among species and, if correct, would provide important insights for understanding and predicting the dynamics of interacting populations. We studied the dynamical behavior of a two-species aquatic laboratory community encompassing the interactions between a demographically structured herbivore population, a primary producer, and a mineral resource, yet still amenable to description and parameterization using a mathematical model. The qualitative dynamical behavior of our experimental system, that is, cycles, equilibria, and extinction, is highly predictable by a simple nonlinear model. PMID:11082063

  13. A derivation of Holling's type I, II and III functional responses in predator-prey systems

    E-print Network

    Dawes, Jon

    of these ODEs is the so-called Rosenzweig­MacArthur model in which various interaction rates between] and in the recent book [2] provides ample motivation for the careful examination of the foundations on which. There are of course contributions by many subsequent authors, including of particular note Rosenzweig and Mac

  14. Advances in molecular ecology: tracking trophic links through predator-prey food-webs

    Microsoft Academic Search

    S. K. SHEPPARD; J. D. HARWOOD

    2005-01-01

    Summary 1. It is not always possible to track trophic interactions between predators and prey by direct observation. This is especially true when observing small or elusive animals with cryptic food-web ecology. Gut and\\/or faecal analysis can sometimes allow prey remains to be identified visually but is only possible when a component of the diet is resistant to digestion. In

  15. Environmental fluctuations restrict eco-evolutionary dynamics in predator-prey system.

    PubMed

    Hiltunen, Teppo; Ayan, Gökçe B; Becks, Lutz

    2015-06-01

    Environmental fluctuations, species interactions and rapid evolution are all predicted to affect community structure and their temporal dynamics. Although the effects of the abiotic environment and prey evolution on ecological community dynamics have been studied separately, these factors can also have interactive effects. Here we used bacteria-ciliate microcosm experiments to test for eco-evolutionary dynamics in fluctuating environments. Specifically, we followed population dynamics and a prey defence trait over time when populations were exposed to regular changes of bottom-up or top-down stressors, or combinations of these. We found that the rate of evolution of a defence trait was significantly lower in fluctuating compared with stable environments, and that the defence trait evolved to lower levels when two environmental stressors changed recurrently. The latter suggests that top-down and bottom-up changes can have additive effects constraining evolutionary response within populations. The differences in evolutionary trajectories are explained by fluctuations in population sizes of the prey and the predator, which continuously alter the supply of mutations in the prey and strength of selection through predation. Thus, it may be necessary to adopt an eco-evolutionary perspective on studies concerning the evolution of traits mediating species interactions. PMID:25994670

  16. The limits of adaptation: humans and the predator-prey arms race.

    PubMed

    Vermeij, Geerat J

    2012-07-01

    In the history of life, species have adapted to their consumers by evolving a wide variety of defenses. By contrast, animal species harvested in the wild by humans have not adapted structurally. Nonhuman predators have high failure rates at one or more stages of an attack, indicating that victim species have spatial refuges or phenotypic defenses that permit further functional improvement. A new compilation confirms that species in the wild cannot achieve immunity from human predation with structural defenses. The only remaining options are to become undesirable or to live in or escape to places where harvesting by people is curtailed. Escalation between prey defenses and predators' weapons may be restricted under human dominance to interactions involving those low-level predators that have benefited from human overexploitation of top consumers. PMID:22759280

  17. Mechanisms of adaptation in a predator-prey arms race: TTX-resistant sodium channels.

    PubMed

    Geffeney, Shana; Brodie, Edmund D; Ruben, Peter C; Brodie, Edmund D

    2002-08-23

    Populations of the garter snake Thamnophis sirtalis have evolved geographically variable resistance to tetrodotoxin (TTX) in a coevolutionary arms race with their toxic prey, newts of the genus Taricha. Here, we identify a physiological mechanism, the expression of TTX-resistant sodium channels in skeletal muscle, responsible for adaptive diversification in whole-animal resistance. Both individual and population differences in the ability of skeletal muscle fibers to function in the presence of TTX correlate closely with whole-animal measures of TTX resistance. Demonstration of individual variation in an essential physiological function responsible for the adaptive differences among populations is a step toward linking the selective consequences of coevolutionary interactions to geographic and phylogenetic patterns of diversity. PMID:12193784

  18. Nonlinearities lead to qualitative differences in population dynamics of predator-prey systems.

    PubMed

    Ameixa, Olga M C C; Messelink, Gerben J; Kindlmann, Pavel

    2013-01-01

    Since typically there are many predators feeding on most herbivores in natural communities, understanding multiple predator effects is critical for both community and applied ecology. Experiments of multiple predator effects on prey populations are extremely demanding, as the number of treatments and the amount of labour associated with these experiments increases exponentially with the number of species in question. Therefore, researchers tend to vary only presence/absence of the species and use only one (supposedly realistic) combination of their numbers in experiments. However, nonlinearities in density dependence, functional responses, interactions between natural enemies etc. are typical for such systems, and nonlinear models of population dynamics generally predict qualitatively different results, if initial absolute densities of the species studied differ, even if their relative densities are maintained. Therefore, testing combinations of natural enemies without varying their densities may not be sufficient. Here we test this prediction experimentally. We show that the population dynamics of a system consisting of 2 natural enemies (aphid predator Adalia bipunctata (L.), and aphid parasitoid, Aphidius colemani Viereck) and their shared prey (peach aphid, Myzus persicae Sulzer) are strongly affected by the absolute initial densities of the species in question. Even if their relative densities are kept constant, the natural enemy species or combination thereof that most effectively suppresses the prey may depend on the absolute initial densities used in the experiment. Future empirical studies of multiple predator - one prey interactions should therefore use a two-dimensional array of initial densities of the studied species. Varying only combinations of natural enemies without varying their densities is not sufficient and can lead to misleading results. PMID:23638107

  19. Nonlinearities Lead to Qualitative Differences in Population Dynamics of Predator-Prey Systems

    PubMed Central

    Ameixa, Olga M. C. C.; Messelink, Gerben J.; Kindlmann, Pavel

    2013-01-01

    Since typically there are many predators feeding on most herbivores in natural communities, understanding multiple predator effects is critical for both community and applied ecology. Experiments of multiple predator effects on prey populations are extremely demanding, as the number of treatments and the amount of labour associated with these experiments increases exponentially with the number of species in question. Therefore, researchers tend to vary only presence/absence of the species and use only one (supposedly realistic) combination of their numbers in experiments. However, nonlinearities in density dependence, functional responses, interactions between natural enemies etc. are typical for such systems, and nonlinear models of population dynamics generally predict qualitatively different results, if initial absolute densities of the species studied differ, even if their relative densities are maintained. Therefore, testing combinations of natural enemies without varying their densities may not be sufficient. Here we test this prediction experimentally. We show that the population dynamics of a system consisting of 2 natural enemies (aphid predator Adalia bipunctata (L.), and aphid parasitoid, Aphidius colemani Viereck) and their shared prey (peach aphid, Myzus persicae Sulzer) are strongly affected by the absolute initial densities of the species in question. Even if their relative densities are kept constant, the natural enemy species or combination thereof that most effectively suppresses the prey may depend on the absolute initial densities used in the experiment. Future empirical studies of multiple predator – one prey interactions should therefore use a two-dimensional array of initial densities of the studied species. Varying only combinations of natural enemies without varying their densities is not sufficient and can lead to misleading results. PMID:23638107

  20. Schoolyard Symbiosis.

    ERIC Educational Resources Information Center

    Allard, David W.

    1996-01-01

    Discusses different types of symbiosis--mutualism, commensalism, and parasitism--and examples of each type including lichens, legumes, mistletoe, and epiphytes. Describes how teachers can use these examples in the study of symbiosis which allows teachers to focus on many basic concepts in evolution, cell biology, ecology, and other fields of…

  1. Lectin\\/glycan interactions play a role in recognition in a coral\\/dinoflagellate symbiosis

    Microsoft Academic Search

    Elisha M. Wood-Charlson; Lea L. Hollingsworth; Dave A. Krupp; Virginia M. Weis

    2006-01-01

    Summary Recognition is an important stage in the establish- ment of highly specific mutualistic associations. Yet, for the majority of symbioses, very few of the mecha- nisms involved in recognition and specificity are known. In this study, we provide evidence for a rec- ognition mechanism at the onset of symbiosis between larvae of the coral Fungia scutaria and their endosymbiotic

  2. Efficacy, prey stage preference and optimum predator–prey ratio of the predatory mite, Neoseiulus longispinosus Evans (Acari: Phytoseiidae) to control the red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae) infesting tea

    Microsoft Academic Search

    Vattakandy Jasin Rahman; Azariah Babu; Amsalingam Roobakkumar; Kandasamy Perumalsamy; Duraikkannu Vasanthakumar; Mariappan Sankara Rama Subramaniam

    2011-01-01

    The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days

  3. Efficacy, prey stage preference and optimum predator–prey ratio of the predatory mite, Neoseiulus longispinosus Evans (Acari: Phytoseiidae) to control the red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae) infesting tea

    Microsoft Academic Search

    Vattakandy Jasin Rahman; Azariah Babu; Amsalingam Roobakkumar; Kandasamy Perumalsamy; Duraikkannu Vasanthakumar; Mariappan Sankara Rama Subramaniam

    2012-01-01

    The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days

  4. The Mycorrhizosphere Effect: A Multitrophic Interaction Complex Improves Mycorrhizal Symbiosis and Plant Growth

    Microsoft Academic Search

    R. Duponnois; A. Galiana; Y. Prin

    \\u000a Mycorrhizal fungi are essential components of sustainable soil-plant systems. Hyphae of arbuscular mycorrhizal (AM) fungi\\u000a play important role in the formation and stability of soil aggregates and contribute to the composition of plant community\\u000a structures. Mycorrhizal symbiosis generally increases root exudation and influences rhizosphere microbial communities. Mycorrhizal\\u000a hyphae exude chemical compounds that have a selective effect on the microbial communities

  5. Hydrodynamic patterns from fast-starts in teleost fish and their possible relevance to predator-prey interactions.

    PubMed

    Niesterok, Benedikt; Hanke, Wolf

    2013-02-01

    Fast-starts are distributed over a wide phylogenetic range of fish and are used for different purposes such as striking at prey or escaping from predators. Here we investigated 42 fast-starts of rainbow trouts (Oncorhynchus mykiss) elicited by a startle stimulus. We investigated the patterns of water movements left behind by the escaping fish and their possible value as a source of information to piscivorous predators that rely on hydrodynamic sensory systems. Particle image velocimetry (PIV) measurements revealed a temporal extension of up to 25.5 min and a spatial extension of up to 1.53 m (extrapolated) for a certain flow structure called jet 1, that is the flow produced by the tail fin. Duration and spatial extension of jet 2, the flow produced by the body, were on average lower, and both jets differed in size. The fish escaped in a mean direction approximately parallel to jet 1, and antiparallel to jet 2, with a range well above 200°. This study quantified the flow patterns generated by escaping fish and, as piscivorous predators would greatly benefit from being able to analyse these flow patterns, provides cues for the behavioural and physiological investigation of hydrodynamic sensory systems. PMID:23180046

  6. Linking predator-prey interactions with exposure to a trophically transmitted parasite using PCR-based analyses.

    PubMed

    Luong, Lien T; Chapman, Eric G; Harwood, James D; Hudson, Peter J

    2013-01-01

    Parasite transmission is determined by the rate of contact between a susceptible host and an infective stage and susceptibility to infection given an exposure event. Attempts to measure levels of variation in exposure in natural populations can be especially challenging. The level of exposure to a major class of parasites, trophically transmitted parasites, can be estimated by investigating the host's feeding behaviour. Since the parasites rely on the ingestion of infective intermediate hosts for transmission, the potential for exposure to infection is inherently linked to the definitive host's feeding ecology. Here, we combined epidemiological data and molecular analyses (polymerase chain reaction) of the diet of the definitive host, the white-footed mouse (Peromyscus leucopus), to investigate temporal and individual heterogeneities in exposure to infection. Our results show that the consumption of cricket intermediate hosts accounted for much of the variation in infection; mice that had consumed crickets were four times more likely to become infected than animals that tested negative for cricket DNA. In particular, pregnant female hosts were three times more likely to consume crickets, which corresponded to a threefold increase in infection compared with nonpregnant females. Interestingly, males in breeding condition had a higher rate of infection even though breeding males were just as likely to test positive for cricket consumption as nonbreeding males. These results suggest that while heterogeneity in host diet served as a strong predictor of exposure risk, differential susceptibility to infection may also play a key role, particularly among male hosts. By combining PCR analyses with epidemiological data, we revealed temporal variation in exposure through prey consumption and identified potentially important individual heterogeneities in parasite transmission. PMID:23110593

  7. Reciprocity in predator–prey interactions: exposure to defended prey and predation risk affects intermediate predator life history and morphology

    Microsoft Academic Search

    Edd Hammill; Andrew P. Beckerman

    2010-01-01

    A vast body of literature exists documenting the morphological, behavioural and life history changes that predators induce\\u000a in prey. However, little attention has been paid to how these induced changes feed back and affect the predators’ life history\\u000a and morphology. Larvae of the phantom midge Chaoborus flavicans are intermediate predators in a food web with Daphnia pulex as the basal

  8. Transport of inertial particles by Lagrangian coherent structures: application to predator-prey interaction in jellyfish feeding

    Microsoft Academic Search

    J. O. D ABIRI

    We use a dynamical systems approach to identify coherent structures from often chaotic motions of inertial particles in open flows. We show that particle Lagrangian coherent structures (pLCS) act as boundaries between regions in which particles have different kinematics. They provide direct geometric information about the motion of ensembles of inertial particles, which is helpful to understand their transport. As

  9. Light-Limitation on Predator-Prey Interactions: Consequences for Metabolism and Locomotion of Deep-Sea Cephalopods

    Microsoft Academic Search

    BRAD A. SEIBEL; ERIK V. THUESEN; JAMES J. CHILDRESS

    2000-01-01

    The present study attempts to correlate the me- tabolism and locomotory behavior of 25 species of midwa- ter Cephalopoda from California and Hawaii with the maximal activities of key metabolic enzymes in various locomotory muscle tissues. Citrate synthase (CS) and octo- pine dehydrogenase (ODH) activities were used as indica- tors of aerobic and anaerobic metabolic potential respec- tively. CS activity

  10. Fuzzy Cellular Model for Predator-Prey Interaction Applied to the Control of Plagues in a Peppers Cropping

    Microsoft Academic Search

    Cecilia Leal-Ramirez; Oscar Castillo; Antonio Rodriguez-Diaz

    \\u000a The control of plagues is the regulation and the handling of some species referred to as plagues, normally these are species\\u000a that affect the ecology and the economy of a certain location. The search for solutions to the important economic incidence\\u000a of the plagues in the croppings has had an evolution throughout the last two decades. In the studies of

  11. Symbiosis: An Evolutionary Innovator.

    ERIC Educational Resources Information Center

    Case, Emily

    2003-01-01

    Defines symbiosis and describes the connection between symbiosis and evolution, how it is described in science textbooks, and genetic variability. Discusses educational policy and science curriculum content. (YDS)

  12. Multiple limit cycles in a Gause type predator-prey model with Holling type III functional response and Allee effect on prey.

    PubMed

    González-Olivares, Eduardo; Rojas-Palma, Alejandro

    2011-06-01

    This work aims to examine the global behavior of a Gause type predator-prey model considering two aspects: (i) the functional response is Holling type III and, (ii) the prey growth is affected by the Allee effect. We prove the origin of the system is an attractor equilibrium point for all parameter values. It has also been shown that it is the ?-limit of a wide set of trajectories of the system, due to the existence of a separatrix curve determined by the stable manifold of the equilibrium point (m,0), which is associated to the Allee effect on prey. When a weak Allee effect on the prey is assumed, an important result is obtained, involving the existence of two limit cycles surrounding a unique positive equilibrium point: the innermost cycle is unstable and the outermost stable. This property, not yet reported in models considering a sigmoid functional response, is an important aspect for ecologists to acknowledge as regards the kind of tristability shown here: (1) the origin; (2) an interior equilibrium; and (3) a limit cycle of large amplitude. These models have undoubtedly been rather sensitive to disturbances and require careful management in applied conservation and renewable resource contexts. PMID:20830610

  13. PHYSICAL REVIEW E 86, 056203 (2012) Turing patterns and apparent competition in predator-prey food webs on networks

    E-print Network

    de Aguiar, Marcus A. M.

    2012-01-01

    network such that predators and prey interact locally in each patch and diffuse through connected nodes and predators that interact by consuming common prey. We show that the Turing patterns of population density] describes the interaction between one species of prey and one species of predator that interact locally

  14. Modelling symbiosis in biological and social systems

    E-print Network

    Yukalov, V I; Sornette, D

    2010-01-01

    We introduce a general mathematical model of symbiosis between different entities by taking into account the influence of each species on the carrying capacities of the others. The modeled entities can pertain to biological and ecological societies or to social, economic and financial societies. Our model includes three basic types: symbiosis with direct mutual interactions, symbiosis with asymmetric interactions, and symbiosis without direct interactions. In all cases, we provide a complete classification of all admissible dynamical regimes. The proposed model of symbiosis turned out to be very rich, as it exhibits four qualitatively different regimes: convergence to stationary states, unbounded exponential growth, finite-time singularity, and finite-time death or extinction of species.

  15. Neo-Symbiosis: The Next Stage in the Evolution of Human Information Interaction

    SciTech Connect

    Griffith, Douglas; Greitzer, Frank L.

    2008-03-01

    We re-address the vision of human-computer symbiosis expressed by J. C. R. Licklider nearly a half-century ago, when he wrote: “The hope is that in not too many years, human brains and computing machines will be coupled together very tightly, and that the resulting partnership will think as no human brain has ever thought and process data in a way not approached by the information-handling machines we know today.” (Licklider, 1960). Unfortunately, little progress was made toward this vision over four decades following Licklider’s challenge, despite significant advancements in the fields of human factors and computer science. Licklider’s vision was largely forgotten. However, recent advances in information science and technology, psychology, and neuroscience have rekindled the potential of making the Licklider’s vision a reality. This paper provides a historical context for and updates the vision, and it argues that such a vision is needed as a unifying framework for advancing IS&T.

  16. Review Behaviour and indirect interactions in food webs of plant-inhabiting arthropods

    Microsoft Academic Search

    Arne Janssen; Angelo Pallini; Madelaine Venzon; Maurice W. Sabelis

    1998-01-01

    With the increased use of biological control agents, artificial food webs are created in agricultural crops and the interactions between plants, herbivores and natural enemies change from simple tritrophic interactions to more complex food web interactions. Therefore, herbivore densities will not only be determined by direct predator–prey interactions and direct and indirect defence of plants against herbivores, but also by

  17. Species interactions and coevolution Scott L. Nuismer

    E-print Network

    Gomulkiewicz, Richard

    Coevolution Focus on this project today #12;An example of spatially structured coevolution: toxic newts and resistant snakes Thamnophis sirtalis Taricha + = · Predator-prey interaction Butch Brodie #12;Toxic newts Taricha granulosa · Newts contain Tetrodotoxin, a potent neurotoxin · Some newts contain enough toxin

  18. Interannual variability in a predatorprey interaction: climate,

    E-print Network

    Interannual variability in a predator­prey interaction: climate, chaetognaths and copepods, compared to 1997, when Pseudocalanus and Acartia were the primary prey. Predation by S. elegans removed ;prey are copepods (Feigenbaum and Maris, 1984). Sev- eral studies have shown that chaetognath predation

  19. "Prey Play": Learning about Predators and Prey through an Interactive, Role-Play Game

    ERIC Educational Resources Information Center

    Deaton, Cynthia C. M.; Dodd, Kristen; Drennon, Katherine; Nagle, Jack

    2012-01-01

    "Prey Play" is an interactive role-play activity that provides fifth-grade students with opportunities to examine predator-prey interactions. This four-part, role-play activity allows students to take on the role of a predator and prey as they reflect on the behaviors animals exhibit as they collect food and interact with one another, as well as…

  20. Mandible-Powered Escape Jumps in Trap-Jaw Ants Increase Survival Rates during Predator-Prey Encounters.

    PubMed

    Larabee, Fredrick J; Suarez, Andrew V

    2015-01-01

    Animals use a variety of escape mechanisms to increase the probability of surviving predatory attacks. Antipredator defenses can be elaborate, making their evolutionary origin unclear. Trap-jaw ants are known for their rapid and powerful predatory mandible strikes, and some species have been observed to direct those strikes at the substrate, thereby launching themselves into the air away from a potential threat. This potential escape mechanism has never been examined in a natural context. We studied the use of mandible-powered jumping in Odontomachus brunneus during their interactions with a common ant predator: pit-building antlions. We observed that while trap-jaw ant workers escaped from antlion pits by running in about half of interactions, in 15% of interactions they escaped by mandible-powered jumping. To test whether escape jumps improved individual survival, we experimentally prevented workers from jumping and measured their escape rate. Workers with unrestrained mandibles escaped from antlion pits significantly more frequently than workers with restrained mandibles. Our results indicate that some trap-jaw ant species can use mandible-powered jumps to escape from common predators. These results also provide a charismatic example of evolutionary co-option, where a trait that evolved for one function (predation) has been co-opted for another (defense). PMID:25970637

  1. Mandible-Powered Escape Jumps in Trap-Jaw Ants Increase Survival Rates during Predator-Prey Encounters

    PubMed Central

    Larabee, Fredrick J.; Suarez, Andrew V.

    2015-01-01

    Animals use a variety of escape mechanisms to increase the probability of surviving predatory attacks. Antipredator defenses can be elaborate, making their evolutionary origin unclear. Trap-jaw ants are known for their rapid and powerful predatory mandible strikes, and some species have been observed to direct those strikes at the substrate, thereby launching themselves into the air away from a potential threat. This potential escape mechanism has never been examined in a natural context. We studied the use of mandible-powered jumping in Odontomachus brunneus during their interactions with a common ant predator: pit-building antlions. We observed that while trap-jaw ant workers escaped from antlion pits by running in about half of interactions, in 15% of interactions they escaped by mandible-powered jumping. To test whether escape jumps improved individual survival, we experimentally prevented workers from jumping and measured their escape rate. Workers with unrestrained mandibles escaped from antlion pits significantly more frequently than workers with restrained mandibles. Our results indicate that some trap-jaw ant species can use mandible-powered jumps to escape from common predators. These results also provide a charismatic example of evolutionary co-option, where a trait that evolved for one function (predation) has been co-opted for another (defense). PMID:25970637

  2. Spatial, temporal and spectral structure of the turbulence-flow interaction at the L-H transition

    NASA Astrophysics Data System (ADS)

    Estrada, T.; Ascasíbar, E.; Blanco, E.; Cappa, A.; Diamond, P. H.; Happel, T.; Hidalgo, C.; Liniers, M.; van Milligen, B. Ph; Pastor, I.; Tafalla, D.; the TJ-II Team

    2012-12-01

    The physical mechanisms behind the L-H transition have been experimentally studied in the TJ-II plasmas. The spatial, temporal and spectral structure of the interaction between turbulence and flows has been studied close to the L-H transition threshold conditions. The temporal dynamics of the turbulence-flow interaction displays a predator-prey relationship and both, radial outward and inward propagation velocities of the turbulence-flow front have been measured. Moreover, the turbulence scales involved in the energy transfer of the predator-prey process have been identified.

  3. Feedbacks between protistan single-cell activity and bacterial physiological structure reinforce the predator/prey link in microbial foodwebs

    PubMed Central

    Sintes, Eva; del Giorgio, Paul A.

    2014-01-01

    The trophic interactions between bacteria and their main predators, the heterotrophic nanoflagellates (HNFs), play a key role in the structuring and functioning of aquatic microbial food webs. Grazing regulation of bacterial communities, both of biomass and community structure, have been frequently reported. Additionally, bottom-up responses of the HNF at the population level (numerical responses) have also been extensively described. However, the functional response of HNF at the single-cell level has not been well explored. In this study, we concurrently measured the physiological structure of bacterial communities and HNF single-cell activities during re-growth cultures of natural aquatic communities. We found that changes in the abundance and proportion of the preferred, highly active bacterial prey, caused by the feeding activity of their predators (HNF), induced a negative feedback effect on the single-cell activity of these HNF. These shifts in the specific cellular activity of HNF occur at a much shorter time scale than population level shifts in flagellate abundance, and offer a complementary mechanism to explain not only the tight coupling between bacteria and HNF, but also the relative constancy of bacterial abundance in aquatic ecosystems. PMID:25250018

  4. Parallel predatorprey interaction for evolutionary multi-objective optimization

    E-print Network

    Paris-Sud XI, Université de

    Parallel predator­prey interaction for evolutionary multi-objective optimization Christian Grimme decade, the predator­prey model (PPM) has emerged as an alternative algorithmic approach to multi parallelization potential for the model. Keywords Multi-objective optimization Á Predator prey model Á

  5. Integrating models to investigate critical phenological overlaps in complex ecological interactions: the mountain pine beetle-fungus symbiosis.

    PubMed

    Addison, Audrey; Powell, James A; Bentz, Barbara J; Six, Diana L

    2015-03-01

    The fates of individual species are often tied to synchronization of phenology, however, few methods have been developed for integrating phenological models involving linked species. In this paper, we focus on mountain pine beetle (MPB, Dendroctonus ponderosae) and its two obligate mutualistic fungi, Grosmannia clavigera and Ophiostoma montium. Growth rates of all three partners are driven by temperature, and their idiosyncratic responses affect interactions at important life stage junctures. One critical phase for MPB-fungus symbiosis occurs just before dispersal of teneral (new) adult beetles, when fungi are acquired and transported in specialized structures (mycangia). Before dispersal, fungi must capture sufficient spatial resources within the tree to ensure contact with teneral adults and get packed into mycangia. Mycangial packing occurs at an unknown time during teneral feeding. We adapt thermal models predicting fungal growth and beetle development to predict overlap between the competing fungi and MPB teneral adult feeding windows and emergence. We consider a spectrum of mycangial packing strategies and describe them in terms of explicit functions with unknown parameters. Rates of growth are fixed by laboratory data, the unknown parameters describing various packing strategies, as well as the degree to which mycangial growth is slowed in woody tissues as compared to agar, are determined by maximum likelihood and two years of field observations. At the field location used, the most likely fungus acquisition strategy for MPB was packing mycangia just prior to emergence. Estimated model parameters suggested large differences in the relative growth rates of the two fungi in trees at the study site, with the most likely model estimating that G. clavigera grew approximately twenty-five times faster than O. montium under the bark, which is completely unexpected in comparison with observed fungal growth on agar. PMID:25556687

  6. [Evolution of legume-rhizobium symbiosis for an improved ecological efficiency and genotypic specificity of partner interactions].

    PubMed

    Provorov, N A; Vorob'ev, N I

    2011-03-01

    Mathematical simulation of the evolution of polymorphic legume-rhizobium symbiosis showed that co-evolution of the partners for an improved ecological efficiency of symbiosis is greatly stimulated when low-active N2-fixing and non-N2-fixing strains of nodule bacteria are prohibited from colonizing nodules. The results of analysis of the model were collated with the comparative morphology of the infection process in various legumes, and its was assumed that mechanisms controlling bacterial reproduction in nodules arose in early evolution of symbiosis in primitive legumes owing to a transition from mixed to clonal infection. The development of such mechanisms was associated with adaptively valuable macroevolutionary transformations of symbiosis and directed its microevolution towards a parallel increase in the specificity and efficiency of mutualism. The increase was due to a reorganization of selective processes in endosymbiotic bacterial populations, which was based on changes in their genetic and spatial structures and optimized metabolic feedbacks between the partners (preferential allocation of photosynthesis products to the most active N2-fixing strains). PMID:21542310

  7. Lectin/glycan interactions play a role in recognition in a coral/dinoflagellate symbiosis

    E-print Network

    algae. This recognition step occurs during initial cellular contact between the symbiotic partners winnowing', and range from molecular signalling involved in inter-partner recognition to inter-microbe symbioses are similar to initial interactions between animal or plant hosts and their parasitic microbes

  8. Recent advances in legume-microbe interactions: recognition, defense response and symbiosis from a genomic perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of legumes to form symbiotic mutualistic relationships with certain bacteria in the Rhizobiales (collectively called rhizobia) and harness the ability of the bacteria to "fix" atmospheric N2 into ammonia has had a tremendous impact on natural and agricultural ecosystems. The interaction ...

  9. Ocean Predator/Prey Populations

    NSDL National Science Digital Library

    Susan Kelly Topic: Population change Course type: Introductory undergraduate course Description Modeling impact of change in food web Learning Goals or Outcomes Students will see how changes on one trophic level ...

  10. Geographic divergence in a species-rich symbiosis: interactions between monterey pines and ectomycorrhizal fungi.

    PubMed

    Hoeksema, Jason D; Hernandez, Jesus Vargas; Rogers, Deborah L; Mendoza, Luciana Luna; Thompson, John N

    2012-10-01

    A key problem in evolutionary biology is to understand how multispecific networks are reshaped by evolutionary and coevolutionary processes as they spread across contrasting environments. To address this problem, we need studies that explicitly evaluate the multispecific guild structure of coevolutionary processes and some of their key outcomes such as local adaptation. We evaluated geographic variation in interactions between most extant native populations of Monterey pine (Pinus radiata) and the associated resistant-propagule community (RPC) of ectomycorrhizal (EM) fungi, using a reciprocal cross-inoculation experiment with all factorial combinations of plant genotypes and soils with fungal guilds from each population. Our results suggest that the pine populations have diverged in community composition of their RPC fungi, and have also diverged genetically in several traits related to interactions of seedlings with particular EM fungi, growth, and biomass allocation. Patterns of genetic variation among pine populations for compatibility with EM fungi differed for the three dominant species of EM fungi, suggesting that Monterey pines can evolve differently in their compatibility with different symbiont species. PMID:23185888

  11. Anim. Behav., 1997, 54, 11471154 Signalling displays during predatorprey interactions in a Puerto Rican anole,

    E-print Network

    Leal, Manuel S.

    Anim. Behav., 1997, 54, 1147­1154 Signalling displays during predator­prey interactions in a Puerto, the flash concealment and predator deterrent hypotheses, were also tested. The flash concealment hypothesis proposes that the sudden display exhibition of signalling behaviour followed by the flight of the animal

  12. Toxicity of the fungicide trifloxystrobin on tadpoles and its effect on fish-tadpole interaction.

    PubMed

    Junges, C M; Peltzer, P M; Lajmanovich, R C; Attademo, A M; Cabagna Zenklusen, M C; Basso, A

    2012-06-01

    Contamination of aquatic systems is a major environmental stress that can interfere with predator-prey interactions, altering prey or predator behavior differentially. We determined toxicity parameters of the fungicide trifloxystrobin (TFS) and examined its effects on predation rate, using a fish predator (Synbranchus marmoratus) and four anuran tadpole species as prey (Rhinella arenarum, Physalaemus santafecinus, Leptodactylus latrans, and Elachistocleis bicolor). TFS was not equally toxic to the four tadpole species, E. bicolor being the most sensitive species, followed by P. santafecinus, R. arenarum, and L. latrans. Predation rates were evaluated using different treatments that combined predator and prey exposed or not to this fungicide. TFS would alter the outcome of eel-tadpole interaction by reducing prey movements; thus, prey detection would decrease and therefore tadpole survival would increase. In addition, eels preyed selectively upon non-exposed tadpoles avoiding the exposed ones almost all throughout the period evaluated. Predation rate differed among prey species; such differences were not due to TFS exposure, but to interspecific differences in behavior. The mechanism that would explain TFS-induced reduction in predation rates remains unclear; however, what is clear is that sublethal TFS concentrations have the potential to alter prey behavior, thereby indirectly altering predator-prey interactions. In addition, we consider that predator-prey relationships are measurable responses of toxicant exposure and provide ecological insight into how contaminants modify predator-prey interactions. PMID:22386454

  13. Evolution of virulence driven by predatorprey interaction: Possible consequences for population dynamics

    E-print Network

    Evolution of virulence driven by predator­prey interaction: Possible consequences for population of a predator can indirectly affect the evolution within its prey since the evolutionarily stable virulence becomes a function of the prey growth rate, which would not be the case in a predator-free system. We find

  14. A dual-genome Symbiosis Chip for coordinate study of signal exchange and development in a prokaryote–host interaction

    PubMed Central

    Barnett, Melanie J.; Toman, Carol J.; Fisher, Robert F.; Long, Sharon R.

    2004-01-01

    The soil-dwelling ?-proteobacterium Sinorhizobium meliloti engages in a symbiosis with legumes: S. meliloti elicits the formation of plant root nodules where it converts dinitrogen to ammonia for use by the plant in exchange for plant photosynthate. To study the coordinate differentiation of S. meliloti and its legume partner during nodule development, we designed a custom Affymetrix GeneChip with the complete S. meliloti genome and ?10,000 probe sets for the plant host, Medicago truncatula. Expression profiling of free-living S. meliloti grown with the plant signal molecule luteolin in defined minimal and rich media or of strains altered in the expression of key regulatory proteins (NodD1, NodD3, and RpoN) confirms previous data and identifies previously undescribed regulatory targets. Analyses of root nodules show that this Symbiosis Chip allows the study of gene expression in both partners simultaneously. Our studies detail nearly 5,000 transcriptome changes in symbiosis and document complex transcriptional profiles of S. meliloti in different environments. PMID:15542588

  15. Species-specific antipredator capacities and prey refuges: interactions between piscivorous perch ( Perca fluviatilis ) and juvenile perch and roach ( Rutilus rutilus )

    Microsoft Academic Search

    Peter Eklöv; Lennart Persson

    1995-01-01

    The outcome of predator-prey interactions depends on the characteristics of predators and prey as well as the structure of the environment. In a replicated field enclosure experiment, we tested the effects of quantity and quality of different prey refuges (no structure, structure forming a partial refuge, and structure forming a complete refuge) on the interaction between piscivorous perch (Perca fluviatilis)

  16. Planet - Disk Symbiosis

    E-print Network

    Sari, R; Sari, Re'em; Goldreich, Peter

    2004-01-01

    Planets form in disks around young stars. Interactions with these disks cause them to migrate and thus affect their final orbital periods. We suggest that the connection between planets and disks may be deeper and involve a symbiotic evolution. By contributing to the outward transport of angular momentum, planets promote disk accretion. Here we demonstrate that planets sufficiently massive to open gaps could be the primary agents driving disk accretion. Those having masses below the gap opening threshold drift inward more rapidly than the disk material and can only play a minor role in its accretion. Eccentricity growth during gap formation may involve an even more intimate symbiosis. Given a small initial eccentricity, just a fraction of a percent, the orbital eccentricity of a massive planet may grow rapidly once a mass in excess of the planet's mass has been repelled to form a gap around the planet's orbit. Then, as the planet's radial excursions approach the gap's width, subsequent eccentricity growth slo...

  17. Computer symbiosis: Emergence of symbiotic behavior through evolution

    SciTech Connect

    Ikegami, Takashi; Kaneko, Kunihiko

    1989-01-01

    Symbiosis is altruistic cooperation between distinct species. It is one of the most effective evolutionary processes, but its dynamics are not well understood as yet. A simple model of symbiosis is introduced, where we consider interactions between hosts and parasites and also mutations of hosts and parasites. It is found that a symbiotic state emerges for a suitable range of mutation rates. The symbiotic state is not static, but dynamically oscillates. Harmful parasites violating symbiosis appear periodically, but are rapidly extinguished by hosts and other parasites, and the symbiotic state is recovered. The emergence of ''Tit for Tat'' strategy to maintain symbiosis is discussed. 4 figs.

  18. Evolution and Signaling Games

    E-print Network

    Zollman, Kevin

    considered the only relevant type of signaling ­ Predator/Prey Interaction ­ Mate Selection ­ Competition) #12;Predator/Prey Predator Prey Chase Move-on Strong 1 1 2 2 Weak 3 0 2 2 #12;Predator/Prey Predator Prey Chase Move-on Strong 1 1 2 2 Weak 3 0 2 2 #12;Predator/Prey Predator Prey Chase Move-on Strong 1 1

  19. How Symbiosis Creates Diversity

    ERIC Educational Resources Information Center

    Lord, Joshua

    2010-01-01

    Diversity in habitats on Earth is astounding--whether on land or in the sea--and this is in part due to symbiosis. The lesson described in this article helps students understand how symbiosis affects different organisms through a fun and engaging game where they match hosts and symbionts based on their respective needs. This 45-minute lesson is…

  20. Preference, specificity and cheating in the arbuscular mycorrhizal symbiosis

    Microsoft Academic Search

    Ian R. Sanders

    2003-01-01

    Arbuscular mycorrhizal symbioses are mutualistic interactions between fungi and most plants. There is considerable interest in this symbiosis because of the strong nutritional benefits conferred to plants and its influence on plant diversity. Until recently, the symbiosis was assumed to be unspecific. However, two studies have now revealed that although it can be largely unspecific with the fungal community composition

  1. Signaling in Plant Disease Resistance and Symbiosis

    Microsoft Academic Search

    Songzi Zhao; Xiaoquan Qi

    2008-01-01

    Interactions between plants and microbes result in plant disease and symbiosis. The former causes considerable economic damage in modern agriculture, while the latter has produced great beneficial effects to our agriculture system. Comparison of the two interactions has revealed that a common panel of signaling pathways might participate in the establishment of the equilibrium between plant and microbes or its

  2. Effects of environmental conditions on predator–prey interactions between white sharks ( Carcharodon carcharias ) and Cape fur seals ( Arctocephalus pusillus pusillus ) at Seal Island, South Africa

    Microsoft Academic Search

    Neil Hammerschlag; R. Aidan Martin; Chris Fallows

    2006-01-01

    Effects of environmental factors on frequency and success rate of 2,546 natural predatory attacks by white sharks, Carcharodon carcharias, on Cape fur seals, Arctocephalus pusillus pusillus, were studied over an 8-year period at Seal Island, South Africa. Attacks occurred primarily during winter months (June–August). Attack frequency increased significantly during northerly winds, during high tides, and within 400 m of the island,

  3. Development of a novel system for isolating genes involved in predator-prey interactions using host independent derivatives of Bdellovibrio bacteriovorus 109J

    Microsoft Academic Search

    Adrian A Medina; Robert M Shanks; Daniel E Kadouri

    2008-01-01

    BACKGROUND: Bdellovibrio bacteriovorus is a gram-negative bacterium that preys upon other gram-negative bacteria. Although the life cycle of Bdellovibrio has been extensively investigated, very little is known about the mechanisms involved in predation. RESULTS: Host-Independent (HI) mutants of B. bacteriovorus were isolated from wild-type strain 109J. Predation assays confirmed that the selected HI mutants retained their ability to prey on

  4. THE EFFECT OF SIZE ON THE FAST-START PERFORMANCE OF RAINBOW TROUT SALMO GAIRDNERI, AND A CONSIDERATION OF PISCIVOROUS PREDATOR-PREY INTERACTIONS

    Microsoft Academic Search

    P. W. WEBB

    SUMMARY The fast-start (acceleration) performance of seven groups of rainbow trout from 9-6 to 387 cm total length was measured in response to d.c. electric shock stimuli. Two fast-start kinematic patterns, L- and S-start were observed. In L-starts the body was bent into an L or U shape and a recoil turn normally accompanied acceleration. Free manoeuvre was not possible

  5. Predator–prey interaction in soil food web: functional response, size-dependent foraging efficiency, and the influence of soil texture

    Microsoft Academic Search

    Karin Hohberg; Walter Traunspurger

    2005-01-01

    In a series of laboratory experiments, we presented carnivorous Macrobiotus richtersi (Tardigrada, Macrobiotidae) with nematode prey to assess their importance as predator. We investigated consumption rate for (a) different prey densities (10–400 prey individuals), (b) different prey biomasses (22–80 ng), (c) different prey species (Pelodera teres, Rhabditidae, versus Acrobeloides nanus, Cephalobidae) and (d) different environments (2-D agar surface versus 3-D sand

  6. Aggressive mimicry, prey-specific predatory behaviour and predator-recognition in the predator-prey interactions of Portia fimbriata and Euryattus sp., jumping spiders from Queensland

    Microsoft Academic Search

    Robert R. Jackson; R. Stimson Wilcox

    1990-01-01

    Adults and large juveniles of Queensland Portia fimbriata, a salticid spider known to prey on other spiders (including other salticids), are shown to use prey-specific predatory behaviour against Euryattus sp., one of the salticids on which it feeds. Euryattus females are unusual because they nest inside suspended rolled-up leaves. P. fimbriata used vibratory displays to lure Euryattus females from their

  7. Planet - Disk Symbiosis

    E-print Network

    Re'em Sari; Peter Goldreich

    2003-07-05

    Planets form in disks around young stars. Interactions with these disks cause them to migrate and thus affect their final orbital periods. We suggest that the connection between planets and disks may be deeper and involve a symbiotic evolution. By contributing to the outward transport of angular momentum, planets promote disk accretion. Here we demonstrate that planets sufficiently massive to open gaps could be the primary agents driving disk accretion. Those having masses below the gap opening threshold drift inward more rapidly than the disk material and can only play a minor role in its accretion. Eccentricity growth during gap formation may involve an even more intimate symbiosis. Given a small initial eccentricity, just a fraction of a percent, the orbital eccentricity of a massive planet may grow rapidly once a mass in excess of the planet's mass has been repelled to form a gap around the planet's orbit. Then, as the planet's radial excursions approach the gap's width, subsequent eccentricity growth slows so that the planet's orbit continues to be confined within the gap.

  8. INDUSTRIAL SYMBIOSIS: Literature and Taxonomy

    Microsoft Academic Search

    Marian R. Chertow

    2000-01-01

    Abstract Industrial symbiosis, as part of the emerging field of industrial ecology, demands resolute attention to the flow of materials and energy through local and regional economies. Industrial symbiosis engages traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and\\/or by-products. The keys to industrial symbiosis are collaboration and the synergistic possibilities

  9. New Approach to Modeling Symbiosis in Biological and Social Systems

    E-print Network

    Yukalov, V I; Sornette, D

    2014-01-01

    We suggest a novel approach to treating symbiotic relations between biological species or social entities. The main idea is the characterisation of symbiotic relations of coexisting species through their mutual influence on their respective carrying capacities, taking into account that this influence can be quite strong and requires a nonlinear functional framework. We distinguish three variants of mutual influence, representing the main types of relations between species: (i) passive symbiosis, when the mutual carrying capacities are influenced by other species without their direct interactions; (ii) active symbiosis, when the carrying capacities are transformed by interacting species; and (iii) mixed symbiosis, when the carrying capacity of one species is influenced by direct interactions, while that of the other species is not. The approach allows us to describe all kinds of symbiosis, mutualism, commensalism, and parasitism within a unified scheme. The case of two symbiotic species is analysed in detail, ...

  10. Symbiosis-mediated outbreaks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Symbiosis simply means "living together" and in its narrowest form can mean two species deriving mutual benefit from the association. Recent studies have made evident that insect associations with microorganisms can range the gamut from casual associations to obligate or context-dependent mutualisms...

  11. Plant-Animal Symbiosis

    Microsoft Academic Search

    S. Schönland

    1895-01-01

    IN your issue of August 22, 1895, Mr. Schwarz describes his finding in South Africa some ants inhabiting the thorns of a mimosa tree, by which he evidently means a species of Acacia. This symbiosis is well known out here, and probably also in Europe, as will be seen by a reference to Schimper's ``Wechsel-beziehungen zwischen Pflanzen und Ameisen im

  12. Plant-Animal Symbiosis

    Microsoft Academic Search

    Ernest H. L. Schwarz

    1895-01-01

    IN Prof. Stewart's collection at the Royal College of Surgeons there is a preparation of a mimosa which protects itself from browsing animals by providing in its great thorns a domicile for a species of vicious, stinging ants. I believe this example of plant-animal symbiosis comes from one of the West Indian Islands, while on the mainland of America the

  13. Computer symbiosis-emergence of symbiotic behavior through evolution

    NASA Astrophysics Data System (ADS)

    Ikegami, Takashi; Kaneko, Kunihiko

    1990-06-01

    Symbiosis is cooperation between distinct species. It is one of the most effective evolutionary processes, but its dynamics are not well understood as yet. A simple model of symbiosis is introduced, in which we consider interactions between hosts and parasites and also mutations of hosts and parasites. The interactions and mutations form a dynamical system on the populations of hosts and parasites. It is found that a symbiotic state emerges for a suitable range of mutation rates. The symbiotic state is not static, but dynamically oscillates. Harmful parasites violating symbiosis appear periodically, but are rapidly extinguished by hosts and other parasites, and the symbiotic state is recovered. The relation between these phenomena and “TIT for TAT” strategy to maintain symbiosis is discussed.

  14. ROS in the Legume Rhizobium Symbiosis

    Microsoft Academic Search

    Karine Mandon; Nicolas Pauly; Alexandre Boscari; Renaud Brouquisse; Pierre Frendo; Bruce Demple; Alain Puppo

    Plants appear to generate reactive oxygen species (ROS) as signaling molecules to control various fundamental processes. With\\u000a this background, this review aims to highlight the involvement of ROS, and their possible interactions with nitric oxide (NO)\\u000a and glutathione (GSH) in the symbiosis between rhizobia and leguminous plants. This compatible interaction, which is very\\u000a important for sustainable agriculture, leads to the

  15. Interactions between the leech Glossiphonia complanata and its gastropod prey

    Microsoft Academic Search

    Christer Briinmark; Bjiirn Malmqvist

    1986-01-01

    Predator-prey interactions between the predatory leech, Glossiphonia complanata, and its gastropod prey were investigated in laboratory experiments, including behavioural observations with the aid of time-lapse video technique. Six gastropod species were investigated, viz. Lymnaea peregra, Planorbis planorbis, Physa fontinalis, Ancylus fluviatilis, Bithynia tentaculata, and Theodoxus fluviatilis. The species studied exhibited anti-predator defences, which had their maximum efficiency at different stages

  16. Symbiosis Teaching Workshop -5th International Symbiosis Society Congress, Vienna, August 4-10, 2006 LAB ACTIVITY

    E-print Network

    Carrapiço, Francisco

    Symbiosis Teaching Workshop - 5th International Symbiosis Society Congress, Vienna, August 4-10, 2006 LAB ACTIVITY FOR SYMBIOSIS TEACHING DISCOVERING AZOLLA;Symbiosis Teaching Workshop - 5th International Symbiosis Society Congress, Vienna

  17. Interactions of biotic and abiotic environmental factors in an ectomycorrhizal symbiosis, and the potential for selection mosaics

    PubMed Central

    Piculell, Bridget J; Hoeksema, Jason D; Thompson, John N

    2008-01-01

    Background Geographic selection mosaics, in which species exert different evolutionary impacts on each other in different environments, may drive diversification in coevolving species. We studied the potential for geographic selection mosaics in plant-mycorrhizal interactions by testing whether the interaction between bishop pine (Pinus muricata D. Don) and one of its common ectomycorrhizal fungi (Rhizopogon occidentalis Zeller and Dodge) varies in outcome, when different combinations of plant and fungal genotypes are tested under a range of different abiotic and biotic conditions. Results We used a 2 × 2 × 2 × 2 factorial experiment to test the main and interactive effects of plant lineage (two maternal seed families), fungal lineage (two spore collections), soil type (lab mix or field soil), and non-mycorrhizal microbes (with or without) on the performance of plants and fungi. Ecological outcomes, as assessed by plant and fungal performance, varied widely across experimental environments, including interactions between plant or fungal lineages and soil environmental factors. Conclusion These results show the potential for selection mosaics in plant-mycorrhizal interactions, and indicate that these interactions are likely to coevolve in different ways in different environments, even when initially the genotypes of the interacting species are the same across all environments. Hence, selection mosaics may be equally as effective as genetic differences among populations in driving divergent coevolution among populations of interacting species. PMID:18507825

  18. Interactions of biotic and abiotic environmental factors in an ectomycorrhizal symbiosis, and the potential for selection mosaics

    Microsoft Academic Search

    Bridget J Piculell; Jason D Hoeksema; John N Thompson

    2008-01-01

    BACKGROUND: Geographic selection mosaics, in which species exert different evolutionary impacts on each other in different environments, may drive diversification in coevolving species. We studied the potential for geographic selection mosaics in plant-mycorrhizal interactions by testing whether the interaction between bishop pine (Pinus muricata D. Don) and one of its common ectomycorrhizal fungi (Rhizopogon occidentalis Zeller and Dodge) varies in

  19. Transcriptome analysis of Sinorhizobium meliloti during symbiosis

    PubMed Central

    Ampe, Frederic; Kiss, Ernö; Sabourdy, Frédérique; Batut, Jacques

    2003-01-01

    Background Rhizobia induce the formation on specific legumes of new organs, the root nodules, as a result of an elaborated developmental program involving the two partners. In order to contribute to a more global view of the genetics underlying this plant-microbe symbiosis, we have mined the recently determined Sinorhizobium meliloti genome sequence for genes potentially relevant to symbiosis. We describe here the construction and use of dedicated nylon macroarrays to study simultaneously the expression of 200 of these genes in a variety of environmental conditions, pertinent to symbiosis. Results The expression of 214 S. meliloti genes was monitored under ten environmental conditions, including free-living aerobic and microaerobic conditions, addition of the plant symbiotic elicitor luteolin, and a variety of symbiotic conditions. Five new genes induced by luteolin have been identified as well as nine new genes induced in mature nitrogen-fixing bacteroids. A bacterial and a plant symbiotic mutant affected in nodule development have been found of particular interest to decipher gene expression at the intermediate stage of the symbiotic interaction. S. meliloti gene expression in the cultivated legume Medicago sativa (alfalfa) and the model plant M. truncatula were compared and a small number of differences was found. Conclusions In addition to exploring conditions for a genome-wide transcriptome analysis of the model rhizobium S. meliloti, the present work has highlighted the differential expression of several classes of genes during symbiosis. These genes are related to invasion, oxidative stress protection, iron mobilization, and signaling, thus emphasizing possible common mechanisms between symbiosis and pathogenesis. PMID:12620125

  20. Differentiation as symbiosis.

    PubMed

    Chigira, M; Watanabe, H

    1994-07-01

    Preservation of the identity of DNA is the ultimate goal of multicellular organisms. An abnormal DNA sequence in cells within an individual means its parasitic nature in cell society as shown in tumors. Somatic gene arrangement and gene mutation in development may be considered as de novo formation of parasites. It is likely that the developmental process with genetic alterations means symbiosis between altered cells and germ line cells preserving genetic information without alterations, when somatic alteration of DNA sequence is a major mechanism of differentiation. According to the selfish gene theory of Dawkins, germ line cells permit symbiosis when somatic cell society derives clear profit for the replication of original DNA copies. PMID:7968715

  1. Detecting predation and scavenging by DNA gut-content analysis: a case study using a soil insect predator-prey system

    Microsoft Academic Search

    Anita Juen; Michael Traugott

    2005-01-01

    White grubs (larvae of Coleoptera: Scarabaeidae) are abundant in below-ground systems and can cause considerable damage to a wide variety of crops by feeding on roots. White grub populations may be controlled by natural enemies, but the predator guild of the European species is barely known. Trophic interactions within soil food webs are difficult to study with conventional methods. Therefore,

  2. The Rhizobium-plant symbiosis.

    PubMed Central

    van Rhijn, P; Vanderleyden, J

    1995-01-01

    Rhizobium, Bradyrhizobium, and Azorhizobium species are able to elicit the formation of unique structures, called nodules, on the roots or stems of the leguminous host. In these nodules, the rhizobia convert atmospheric N2 into ammonia for the plant. To establish this symbiosis, signals are produced early in the interaction between plant and rhizobia and they elicit discrete responses by the two symbiotic partners. First, transcription of the bacterial nodulation (nod) genes is under control of the NodD regulatory protein, which is activated by specific plant signals, flavonoids, present in the root exudates. In return, the nod-encoded enzymes are involved in the synthesis and excretion of specific lipooligosaccharides, which are able to trigger on the host plant the organogenic program leading to the formation of nodules. An overview of the organization, regulation, and function of the nod genes and their participation in the determination of the host specificity is presented. PMID:7708010

  3. Symbiosis Workshop 2011 Symposium Schedule

    E-print Network

    Sachs, Joel

    ://www.sachslab.com/symbiosis-workshop-2011.php Organized by Monica Medina & Joel Sachs #12; Schedule of invited of symbiosis · 12:50-1:00 PM Introduction and welcome to meeting (Monica Medina Batrachochytrium dendrobatidis (Bd) · 1:30-1:50 PM Mónica Medina Recently uncovered

  4. ODEs Course Project: Investigating Nonlinear Ecological Models

    E-print Network

    Slastikov, Valeriy V.

    of interaction between species: cooperation, competition, predator- prey, e.t.c. In this project you will study basic models of predator-prey interaction and competing species interaction. Predator-Prey. The predator-prey. The interaction terms measure the efficiency of predator in converting food into more births (bxy), and the rate

  5. Molecular diagnosis of a previously unreported predator-prey association in coffee: Karnyothrips flavipes Jones (Thysanoptera: Phlaeothripidae) predation on the coffee berry borer.

    PubMed

    Jaramillo, Juliana; Chapman, Eric G; Vega, Fernando E; Harwood, James D

    2010-03-01

    The coffee berry borer, Hypothenemus hampei, is the most important pest of coffee throughout the world, causing losses estimated at US $500 million/year. The thrips Karnyothrips flavipes was observed for the first time feeding on immature stages of H. hampei in April 2008 from samples collected in the Kisii area of Western Kenya. Since the trophic interactions between H. hampei and K. flavipes are carried out entirely within the coffee berry, and because thrips feed by liquid ingestion, we used molecular gut-content analysis to confirm the potential role of K. flavipes as a predator of H. hampei in an organic coffee production system. Species-specific COI primers designed for H. hampei were shown to have a high degree of specificity for H. hampei DNA and did not produce any PCR product from DNA templates of the other insects associated with the coffee agroecosystems. In total, 3,327 K. flavipes emerged from 17,792 H. hampei-infested berries collected from the field between April and September 2008. Throughout the season, 8.3% of K. flavipes tested positive for H. hampei DNA, although at times this figure approached 50%. Prey availability was significantly correlated with prey consumption, thus indicating the potential impact on H. hampei populations. PMID:20094879

  6. Symbiosis of Thioautotrophic Bacteria with Riftia Introduction

    E-print Network

    Stewart, Frank

    1 Symbiosis of Thioautotrophic Bacteria with Riftia pachyptila Introduction The symbiosis between-rich hydrothermal vents. In the decade following the initial description of this symbiosis in 1981 (Cavanaugh et al of chemosynthetic symbioses. Specifically, for the R. pachyptila symbiosis, researchers provided new insights

  7. Modelling Ammonium Transporters in Arbuscular Mycorrhiza Symbiosis

    E-print Network

    Troina, Angelo

    Modelling Ammonium Transporters in Arbuscular Mycorrhiza Symbiosis Mario Coppo1 , Ferruccio Damiani, the most wide-spread plant-fungus symbiosis on earth. Inves- tigating this kind of symbiosis is considered), the most widespread symbiosis between plants and fungi, got into the focus of research because of its

  8. Behavioral Interactions Between Aphaenogaster rudis (Hymenoptera: Formicidae) and Reticulitermes flavipes (Isoptera: Rhinotermitidae): The Importance of Physical Barriers

    Microsoft Academic Search

    Grzegorz Buczkowski; Gary Bennett

    2008-01-01

    Predation pressure from ants is a major driving force in the adaptive evolution of termite defense strategies and termites\\u000a have evolved elaborate chemical and physical defenses to protect themselves against ants. We examined predator–prey interactions\\u000a between the woodland ant, Aphaenogaster rudis (Emery) and the eastern subterranean termite, Reticulitermes flavipes (Kollar), two sympatric species widely distributed throughout deciduous forests in eastern

  9. Bark Beetle-Fungal Symbiosis: Context Dependency in Complex Associations

    Microsoft Academic Search

    K. D. KLEPZIGl; D. L. SIX

    Recent thinking in symbiosis research has emphasized a holistic consideration of these complex interactions. Bark beetles and their associated microbes are one group which has previously not been addressed in this manner. We review the study of symbiotic interactions among bark beetles and microbes in light of this thinking. We describe the considerable progress already made, examine areas where further

  10. Optimal Foraging and Predator-Prey Dynamics

    PubMed

    Krivan

    1996-06-01

    A system consisting of a population of predators and two types of prey is considered. The dynamics of the system is described by differential equations with controls. The controls model how predators forage on each of the two types of prey. The choice of these controls is based on the standard assumption in the theory of optimal foraging which requires that each predator maximizes the net rate of energy intake during foraging. Since this choice depends on the densities of populations involved, this allows us to link the optimal behavior of an individual with the dynamics of the whole system. Simple qualitative analysis and some simulations show the qualitative behavior of such a system. The effect of the optimal diet choice on the stability of the system is discussed. PMID:8813025

  11. Expanding genomics of mycorrhizal symbiosis.

    PubMed

    Kuo, Alan; Kohler, Annegret; Martin, Francis M; Grigoriev, Igor V

    2014-01-01

    The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant nutrition, soil health, and carbon cycling. The symbiosis evolved repeatedly and independently as multiple morphotypes [e.g., arbuscular mycorrhizae (AM), ectomycorrhizal (ECM)] in multiple fungal clades (e.g., phyla Glomeromycota, Ascomycota, Basidiomycota). The accessibility and cultivability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first three mycorrhizal fungal genomes, representing two morphotypes and three phyla. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolve through loss of plant cell wall-degrading enzymes (PCWDEs) and expansion of lineage-specific gene families such as short secreted protein (SSP) effectors. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of families as in Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other two fungi, symbiosis can involve similar solutions as symbiosis-induced SSPs and loss of PCWDEs. The three genomes provide a solid base for addressing fundamental questions about the nature and role of a vital mutualism. PMID:25408690

  12. Ant-plants and fungi: a new threeway symbiosis

    Microsoft Academic Search

    Emmanuel Defossez; Marc-André Selosse; Marie-Pierre Dubois; Laurence Mondolot; Antonella Faccio; Champlain Djieto-Lordon; Doyle McKey; Rumsaïs Blatrix

    2009-01-01

    Summary • Symbioses between plants and fungi, fungi and ants, and ants and plants all play important roles in ecosystems. Symbioses involving all three partners appear to be rare. Here, we describe a novel tripartite symbiosis in which ants and a fungus inhabit domatia of an ant-plant, and present evidence that such interactions are widespread.  We investigated 139 individuals

  13. SYMBIOSIS POINTS FOR LINEAR DIFFERENTIAL SYSTEMS

    E-print Network

    Tsatsomeros, Michael

    SYMBIOSIS POINTS FOR LINEAR DIFFERENTIAL SYSTEMS Michael Neumann and Michael J. Tsatsomeros the notion of a symbiosis point for the system. This is a point in XA(Rn +) such that also the velocity become and remain nondecreasing. We characterize all symbiosis points for the system. We also show

  14. Explorations in Symbiosis on two Multithreaded Architectures

    E-print Network

    Wang, Deli

    Explorations in Symbiosis on two Multithreaded Architectures Allan Snavely \\Lambday , Nick Mitchell \\Lambda , Larry Carter \\Lambday , Jeanne Ferrante \\Lambday , and Dean Tullsen \\Lambda Abstract Symbiosis choices about what jobs to run together. Symbiosis is defined as the mutually beneficial living together

  15. The conflict interaction between two complex systems. Cyclic migration

    E-print Network

    Albeverio, S; Samoilenko, I

    2009-01-01

    We construct and study a discrete time model describing the conflict interaction between two complex systems with non-trivial internal structures. The external conflict interaction is based on the model of alternative interaction between a pair of non-annihilating opponents. The internal conflict dynamics is similar to the one of a predator-prey model. We show that the typical trajectory of the complex system converges to an asymptotic attractive cycle. We propose an interpretation of our model in terms of migration processes.

  16. Interactions between ectomycorrhizal symbiosis and fluorescent pseudomonads on Acacia holosericea: isolation of mycorrhiza helper bacteria (MHB) from a Soudano-Sahelian soil.

    PubMed

    Founoune, Hassna; Duponnois, Robin; Meyer, Jean Marie; Thioulouse, Jean; Masse, Dominique; Chotte, Jean Luc; Neyra, Marc

    2002-07-01

    Abstract Acacia holosericea seedlings were planted in 1-l pots filled with a soil collected from an Australian Acacia plantation in Southern Senegal. After 6 months of culture, mycorrhizosphere soil, roots, galls induced by root-knot nematodes and Rhizobium nodules were sampled from each pot. The diversity of this bacterial group was characterized by siderotyping (pyoverdine IsoElectric Focusing (IEF) analysis) and by restriction fragment length polymorphism (RFLP). The effect of these isolates on the establishment of the ectomycorrhizal symbiosis between an Australian Acacia (A. holosericea) and Pisolithus sp. strain IR100 was studied. In the mycorrhizosphere soil, the population of fluorescent pseudomonads was represented by strains of two different siderovars (groups of bacterial strains presenting an identical pyoverdine-IEF pattern): siderovar 1 (74%) and siderovar 2 (26%). The siderotyping of the isolates around galls of the root-knot nematodes revealed three siderovars (40% from siderovar 1, 40% from siderovar 2 and about 15% from siderovar 3). RFLP of 16S rDNA divided the isolates into four different groups with MspI, two with HhaI and two with HaeIII endonucleases. The establishment of the ectomycorrhizal symbiosis with A. holosericea was promoted by 14 bacterial strains isolated from the mycorrhizosphere soil, three isolates from the roots and four from the galls. Shoot biomass of A. holosericea seedlings was stimulated by eight bacterial isolates from soil, six isolates from galls and seven from roots. These mycorrhiza helper bacteria could have a great ecological importance in tropical areas through the reforestation programs. PMID:19709237

  17. ANNUAL SYMBIOSIS WORKSHOP ---MAY 19-20TH , 2012

    E-print Network

    Sachs, Joel

    2ND ANNUAL SYMBIOSIS WORKSHOP --- MAY 19-20TH , 2012 SYMBIOSIS WORKSHOP 2012 PRELIMINARY SYMPOSIUM SCHEDULE SIERRA NEVADA RESEARCH INSTITUTE HTTP://WWW.SACHSLAB.COM/SYMBIOSIS-WORKSHOP-2012.PHP ORGANIZED BY JOEL L. SACHS

  18. Frankia-actinorhizal plant symbiosis Actinorhizal plants form root nodules in symbiosis with the nitrogen-fixing actinomycete

    E-print Network

    Upchurch, Gary - Department of Biology, Texas State University

    Frankia-actinorhizal plant symbiosis Actinorhizal plants form root nodules in symbiosis with the nitrogen-fixing actinomycete Frankia, which enables them and efficiency of the symbiosis between Frankia and actinorhizal plants

  19. SYMBIOSIS: COOPERATIVE ALGORITHMS FOR MOBILE ROBOTS AND A SENSOR NETWORK

    E-print Network

    Southern California, University of

    SYMBIOSIS: COOPERATIVE ALGORITHMS FOR MOBILE ROBOTS AND A SENSOR NETWORK by Maxim Alexander Batalin - Symbiosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3 Problem Description and Thesis

  20. Evolution of symbiosis with resource allocation from fecundity to survival.

    PubMed

    Fukui, Shin

    2014-05-01

    Symbiosis is one of the most fundamental relationships between or among organisms and includes parasitism (which has negative effects on the fitness of the interacting partner), commensalism (no effect), and mutualism (positive effects). The effects of these interactions are usually assumed to influence a single component of a species' fitness, either survival or fecundity, even though in reality the interaction can simultaneously affect both of these components. I used a dual lattice model to investigate the process of evolution of mutualistic symbiosis in the presence of interactive effects on both survival and fecundity. I demonstrate that a positive effect on survival and a negative effect on fecundity are key to the establishment of mutualism. Furthermore, both the parasitic and the mutualistic behaviour must carry large costs for mutualism to evolve. This helps develop a new understanding of symbiosis as a function of resource allocation, in which resources are shifted from fecundity to survival. The simultaneous establishment of mutualism from parasitism never occurs in two species, but can do so in one of the species as long as the partner still behaves parasitically. This suggests that one of the altruistic behaviours in a mutualistic unit consisting of two species must originate as a parasitic behaviour. PMID:24744057

  1. Organism Interactions

    NSDL National Science Digital Library

    Mrs. Marsh

    2008-09-16

    Complete both parts in the assignment below. At the conclusion of this assignment, you will go to our class testing site on nutips and take a short quiz called \\"Organism Interactions.\\" Objectives: In this activity: 1. Students will define symbiosis and distinguish the type of symbiotic relationship that is occurring; mutualism, commensalism, or parasitism. 2. Students will distinguish competition from symbiosis. Part I. Link to the following website and read the information provided on Symbiosis. As you are reading you ...

  2. Cell Biology of Cnidarian-Dinoflagellate Symbiosis

    PubMed Central

    Allemand, Denis; Weis, Virginia M.

    2012-01-01

    Summary: The symbiosis between cnidarians (e.g., corals or sea anemones) and intracellular dinoflagellate algae of the genus Symbiodinium is of immense ecological importance. In particular, this symbiosis promotes the growth and survival of reef corals in nutrient-poor tropical waters; indeed, coral reefs could not exist without this symbiosis. However, our fundamental understanding of the cnidarian-dinoflagellate symbiosis and of its links to coral calcification remains poor. Here we review what we currently know about the cell biology of cnidarian-dinoflagellate symbiosis. In doing so, we aim to refocus attention on fundamental cellular aspects that have been somewhat neglected since the early to mid-1980s, when a more ecological approach began to dominate. We review the four major processes that we believe underlie the various phases of establishment and persistence in the cnidarian/coral-dinoflagellate symbiosis: (i) recognition and phagocytosis, (ii) regulation of host-symbiont biomass, (iii) metabolic exchange and nutrient trafficking, and (iv) calcification. Where appropriate, we draw upon examples from a range of cnidarian-alga symbioses, including the symbiosis between green Hydra and its intracellular chlorophyte symbiont, which has considerable potential to inform our understanding of the cnidarian-dinoflagellate symbiosis. Ultimately, we provide a comprehensive overview of the history of the field, its current status, and where it should be going in the future. PMID:22688813

  3. Phosphorus and Nitrogen Regulate Arbuscular Mycorrhizal Symbiosis in Petunia hybrida

    PubMed Central

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi. PMID:24608923

  4. A novel reef coral symbiosis

    NASA Astrophysics Data System (ADS)

    Pantos, O.; Bythell, J. C.

    2010-09-01

    Reef building corals form close associations with unicellular microalgae, fungi, bacteria and archaea, some of which are symbiotic and which together form the coral holobiont. Associations with multicellular eukaryotes such as polychaete worms, bivalves and sponges are not generally considered to be symbiotic as the host responds to their presence by forming physical barriers with an active growth edge in the exoskeleton isolating the invader and, at a subcellular level, activating innate immune responses such as melanin deposition. This study describes a novel symbiosis between a newly described hydrozoan ( Zanclea margaritae sp. nov.) and the reef building coral Acropora muricata (= A. formosa), with the hydrozoan hydrorhiza ramifying throughout the coral tissues with no evidence of isolation or activation of the immune systems of the host. The hydrorhiza lacks a perisarc, which is typical of symbiotic species of this and related genera, including species that associate with other cnidarians such as octocorals. The symbiosis was observed at all sites investigated from two distant locations on the Great Barrier Reef, Australia, and appears to be host species specific, being found only in A. muricata and in none of 30 other species investigated at these sites. Not all colonies of A. muricata host the hydrozoans and both the prevalence within the coral population (mean = 66%) and density of emergent hydrozoan hydranths on the surface of the coral (mean = 4.3 cm-2, but up to 52 cm-2) vary between sites. The form of the symbiosis in terms of the mutualism-parasitism continuum is not known, although the hydrozoan possesses large stenotele nematocysts, which may be important for defence from predators and protozoan pathogens. This finding expands the known A. muricata holobiont and the association must be taken into account in future when determining the corals’ abilities to defend against predators and withstand stress.

  5. GAMM-Mitt. 32, No. 1, 47 60 (2009) / DOI 10.1002/gamm.200910004 On the Approximation of Transport Phenomena

    E-print Network

    Blennerhassett, Peter

    2009-01-01

    ranging from the analysis of fluid flow in the ocean and the predator-prey interaction in jelly- fish.: On the Approximation of Transport Phenomena consideration of predator-prey interaction in jellyfish [24

  6. Brain-computer symbiosis.

    PubMed

    Schalk, Gerwin

    2008-03-01

    The theoretical groundwork of the 1930s and 1940s and the technical advance of computers in the following decades provided the basis for dramatic increases in human efficiency. While computers continue to evolve, and we can still expect increasing benefits from their use, the interface between humans and computers has begun to present a serious impediment to full realization of the potential payoff. This paper is about the theoretical and practical possibility that direct communication between the brain and the computer can be used to overcome this impediment by improving or augmenting conventional forms of human communication. It is about the opportunity that the limitations of our body's input and output capacities can be overcome using direct interaction with the brain, and it discusses the assumptions, possible limitations and implications of a technology that I anticipate will be a major source of pervasive changes in the coming decades. PMID:18310804

  7. Friend or foe? A behavioral and stable isotopic investigation of an ant–plant symbiosis

    Microsoft Academic Search

    Chadwick V. Tillberg

    2004-01-01

    In ant–plant symbioses, the behavior of ant inhabitants affects the nature of the interaction, ranging from mutualism to parasitism. Mutualistic species confer a benefit to the plant, while parasites reap the benefits of the interaction without reciprocating, potentially resulting in a negative impact on the host plant. Using the ant–plant symbiosis between Cordia alliodora and its ant inhabitants as a

  8. Model Intestinal Microflora In Computer Simulation (MIMICS) Technical Report

    E-print Network

    Wilkinson, Michael H.F.

    .6 Predator-prey interactions 22 3.7 Decoys in predator-prey interactions 24 3.8 Direct binding site of inactivating substances, protecting sensitive species. 6. Predator-prey interaction. One species may prey Equations for Modelling Bacterial Interactions in the Gut. Michael H.F. Wilkinson Centre for High

  9. OSCILLATIONS IN A SIZE-STRUCTURED PREY-PREDATOR SOUVIK BHATTACHARYA AND MAIA MARTCHEVA

    E-print Network

    Martcheva, Maia

    model, predator escape mechanism 1. Introduction Predator-prey interactions have fascinated mathematical be responsible for the oscillations observed in the predator-prey interactions in nature. The interactions the opposite perspective: we look at the impact of the size of the prey on the predator-prey interaction and we

  10. Ecology, 88(11), 2007, pp. 27442751 2007 by the Ecological Society of America

    E-print Network

    Orrock, John

    MODE AND HABITAT DOMAIN ALTER NONCONSUMPTIVE EFFECTS IN PREDATOR­PREY INTERACTIONS EVAN L. PREISSER,1 interactions. INTRODUCTION Predator­prey interactions can promote persistence or hasten extinction among of the predator­prey interaction. Inasmuch as progress in community ecology depends upon the ability to generate

  11. Rhizobium–legume symbiosis shares an exocytotic pathway required for arbuscule formation

    PubMed Central

    Ivanov, Sergey; Fedorova, Elena E.; Limpens, Erik; De Mita, Stephane; Genre, Andrea; Bonfante, Paola; Bisseling, Ton

    2012-01-01

    Endosymbiotic interactions are characterized by the formation of specialized membrane compartments, by the host in which the microbes are hosted, in an intracellular manner. Two well-studied examples, which are of major agricultural and ecological importance, are the widespread arbuscular mycorrhizal symbiosis and the Rhizobium–legume symbiosis. In both symbioses, the specialized host membrane that surrounds the microbes forms a symbiotic interface, which facilitates the exchange of, for example, nutrients in a controlled manner and, therefore, forms the heart of endosymbiosis. Despite their key importance, the molecular and cellular mechanisms underlying the formation of these membrane interfaces are largely unknown. Recent studies strongly suggest that the Rhizobium–legume symbiosis coopted a signaling pathway, including receptor, from the more ancient arbuscular mycorrhizal symbiosis to form a symbiotic interface. Here, we show that two highly homologous exocytotic vesicle-associated membrane proteins (VAMPs) are required for formation of the symbiotic membrane interface in both interactions. Silencing of these Medicago VAMP72 genes has a minor effect on nonsymbiotic plant development and nodule formation. However, it blocks symbiosome as well as arbuscule formation, whereas root colonization by the microbes is not affected. Identification of these VAMP72s as common symbiotic regulators in exocytotic vesicle trafficking suggests that the ancient exocytotic pathway forming the periarbuscular membrane compartment has also been coopted in the Rhizobium–legume symbiosis. PMID:22566631

  12. Impact of simulated microgravity on the normal developmental time line of an animal-bacteria symbiosis

    PubMed Central

    Foster, Jamie S.; Khodadad, Christina L. M.; Ahrendt, Steven R.; Parrish, Mirina L.

    2013-01-01

    The microgravity environment during space flight imposes numerous adverse effects on animal and microbial physiology. It is unclear, however, how microgravity impacts those cellular interactions between mutualistic microbes and their hosts. Here, we used the symbiosis between the host squid Euprymna scolopes and its luminescent bacterium Vibrio fischeri as a model system. We examined the impact of simulated microgravity on the timeline of bacteria-induced development in the host light organ, the site of the symbiosis. To simulate the microgravity environment, host squid and symbiosis-competent bacteria were incubated together in high-aspect ratio rotating wall vessel bioreactors and examined throughout the early stages of the bacteria-induced morphogenesis. The host innate immune response was suppressed under simulated microgravity; however, there was an acceleration of bacteria-induced apoptosis and regression in the host tissues. These results suggest that the space flight environment may alter the cellular interactions between animal hosts and their natural healthy microbiome. PMID:23439280

  13. PtSRR1, a putative Pisolithus tinctorius symbiosis related receptor gene is expressed during the first hours of mycorrhizal interaction with Castanea sativa roots.

    PubMed

    Acioli-Santos, B; Malosso, E; Calzavara-Silva, C E; Lima, C E P; Figueiredo, A; Sebastiana, M; Pais, M S

    2009-04-01

    PtSRR1 EST was previously identified in the first hours of Pisolithus tinctorius and Castanea sativa interaction. QRT-PCR confirmed PtSRR1 early expression and in silico preliminary translated peptide analysis indicated a strong probability that PtSRR1 be a transmembrane protein. These data stimulate the PtSRR1 gene research during ectomycorrhiza formation. PMID:24031360

  14. Interspecific infanticide deters predators Arne Janssen*, Farid Faraji,

    E-print Network

    Magalhães, Sara

    an example of such a complex predator­prey interaction. We show that (1) the vulnerable stage, predator­prey interactions, stage structure. Ecology Letters (2002) 5: 490­494 I N T R O DU C T I O N There is growing awareness that size structure or age structure is important in predator­prey interactions (de Roos

  15. Journal of Biological Dynamics Vol. 00, No. 0, Month 2009, 112

    E-print Network

    Trenchea, Catalin

    present the analysis of two reaction­diffusion systems modelling predator­prey interactions, where' in an invariant region of phase space. Keywords: predator­prey interaction; Holling type II functional response on reaction­diffusion systems modelling predator­prey interactions with the following general form [20, p. 84

  16. MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser

    E-print Network

    New Hampshire, University of

    influences the survival and predator­prey interactions of early juvenile red king crab Paralithodes habitat structure affects survival and predator-prey interactions of red king crab Paralithodes · Paralithodes camtschaticus · Nursery habitat dynamics · Predator­prey interaction · Habitat complexity · Refuge

  17. Journal of Biological Dynamics Vol. 4, No. 6, November 2010, 559570

    E-print Network

    Garvie, Marcus R

    present the analysis of two reaction­diffusion systems modelling predator­prey interactions, where' in an invariant region of phase space. Keywords: predator­prey interaction; Holling type II functional response modelling predator­prey interactions with the following general form [20, p. 84; 24, p. 71; 35] u t = 1 u

  18. Individual behaviour, space and predator evolution promote persistence in a two-patch system with

    E-print Network

    Holt, Robert D.

    to be a stabilizing force in predator­prey interactions. Recent models, however, have shown that predator switching between prey species, predator switching may help stabilize predator­prey interactions. Keywords both to have a stabilizing effect on predator­prey interactions and to permit the co

  19. Persistence in fluctuating environments for interacting structured populations.

    PubMed

    Roth, Gregory; Schreiber, Sebastian J

    2014-11-01

    Individuals within any species exhibit differences in size, developmental state, or spatial location. These differences coupled with environmental fluctuations in demographic rates can have subtle effects on population persistence and species coexistence. To understand these effects, we provide a general theory for coexistence of structured, interacting species living in a stochastic environment. The theory is applicable to nonlinear, multi species matrix models with stochastically varying parameters. The theory relies on long-term growth rates of species corresponding to the dominant Lyapunov exponents of random matrix products. Our coexistence criterion requires that a convex combination of these long-term growth rates is positive with probability one whenever one or more species are at low density. When this condition holds, the community is stochastically persistent: the fraction of time that a species density goes below ? approaches zero as ? approaches zero. Applications to predator-prey interactions in an autocorrelated environment, a stochastic LPA model, and spatial lottery models are provided. These applications demonstrate that positive autocorrelations in temporal fluctuations can disrupt predator-prey coexistence, fluctuations in log-fecundity can facilitate persistence in structured populations, and long-lived, relatively sedentary competing populations are likely to coexist in spatially and temporally heterogeneous environments. PMID:24311028

  20. Differential spatio-temporal expression of carotenoid cleavage dioxygenases regulates apocarotenoid fluxes during AM symbiosis.

    PubMed

    López-Ráez, Juan A; Fernández, Iván; García, Juan M; Berrio, Estefanía; Bonfante, Paola; Walter, Michael H; Pozo, María J

    2015-01-01

    Apocarotenoids are a class of compounds that play important roles in nature. In recent years, a prominent role for these compounds in arbuscular mycorrhizal (AM) symbiosis has been shown. They are derived from carotenoids by the action of the carotenoid cleavage dioxygenase (CCD) enzyme family. In the present study, using tomato as a model, the spatio-temporal expression pattern of the CCD genes during AM symbiosis establishment and functioning was investigated. In addition, the levels of the apocarotenoids strigolactones (SLs), C13 ?-ionol and C14 mycorradicin (C13/C14) derivatives were analyzed. The results suggest an increase in SLs promoted by the presence of the AM fungus at the early stages of the interaction, which correlated with an induction of the SL biosynthesis gene SlCCD7. At later stages, induction of SlCCD7 and SlCCD1 expression in arbusculated cells promoted the production of C13/C14 apocarotenoid derivatives. We show here that the biosynthesis of apocarotenoids during AM symbiosis is finely regulated throughout the entire process at the gene expression level, and that CCD7 constitutes a key player in this regulation. Once the symbiosis is established, apocarotenoid flux would be turned towards the production of C13/C14 derivatives, thus reducing SL biosynthesis and maintaining a functional symbiosis. PMID:25480008

  1. Effect of predator density dependent dispersal of prey on stability of a predatorprey system

    E-print Network

    Poggiale, Jean-Christophe

    predator­prey interaction on each patch. Thus, we take advantage of two time scales in order to reduce of two parts, one describ- ing the local predator­prey interaction and one describing the dispersal fromEffect of predator density dependent dispersal of prey on stability of a predator­prey system

  2. A predatorprey model with predators using hawk and dove tactics

    E-print Network

    Bravo de la Parra, Rafael

    of the predators. A classical Lotka­Volterra model with self-limiting prey describes the predator­prey interaction on prey density. We assume that the demographic process, predator­prey interactions, acts at a slow timeA predator­prey model with predators using hawk and dove tactics Pierre Auger a,*, Rafael Bravo de

  3. Math. Model. Nat. Phenom. Vol. 4, No. 2, 2009, pp. 140-188

    E-print Network

    Ruan, Shigui

    . Introduction Predator-prey interaction is the fundamental structure in population dynamics. Understanding population dynamics, including predator-prey interactions. We refer to the monographs of Cushing [24 Dynamics of Predator-Prey Models with Discrete Delay S. Ruan Department of Mathematics, University of Miami

  4. Bulletin of Mathematical Biology (2008) 70: 654676 DOI 10.1007/s11538-007-9271-4

    E-print Network

    Lewis, Mark

    2008-01-01

    of interspecific interaction: predator­prey, competition, and mutualism. In a predator­prey relationship density and investigate the role of prey-taxis in spatial predator­prey interactions. For that, we extend- ment of predators to regions of high prey density. This effect leads to the observation that predators

  5. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    PubMed

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes. PMID:25231970

  6. Spatial games with cyclic interactions: the response of empty sites

    NASA Astrophysics Data System (ADS)

    Brown, Bart; Pleimling, Michel

    2015-03-01

    Predator-prey models of the May-Leonard family employ empty sites in a spatial setting as an intermediate step in the reproduction process. This requirement makes the number and arrangement of empty sites important to the formation of space-time patterns. We study the density of empty sites in a stochastic predator-prey model in which the species compete in a cyclic way in two dimensions. In some cases systems of this type quickly form domains of neutral species after which all predation, and therefore, reproduction occur near the interface of competing domains. Using Monte Carlo simulations we investigate the relationship of this density of empty sites to the time-dependent domain length. We further explore the dynamics by introducing perturbations to the interaction rates of the system after which we measure the perturbed density, i.e. the response of empty sites, as the system relaxes. A dynamical scaling behavior is observed in the response of empty sites. This work is supported by the US National Science Foundation through Grant DMR-1205309.

  7. Predator–prey relationships and responses of ungulates and their predators to the establishment of protected areas: A case study of tigers, leopards and their prey in Bardia National Park, Nepal

    Microsoft Academic Search

    Per Wegge; Morten Odden; Chiranjibi Pd. Pokharel; Torstein Storaas

    2009-01-01

    Interactions among sympatric large predators and their prey and how they respond to conservation measures are poorly known. This study examines predictions concerning the effects of establishing a protected area in Nepal on tigers (Panthera tigris), leopards (Panthera pardus), and their ungulate prey. Within a part of the park, after 22 years the total density of wild ungulates had increased

  8. Sustainable agriculture: possible trajectories from mutualistic symbiosis and plant neodomestication

    E-print Network

    Paris-Sud XI, Université de

    Sustainable agriculture: possible trajectories from mutualistic symbiosis and plant. Based on recent findings, new trajectories for agriculture and plant breeding which take into account symbiosis in an innovative ecologically intensive agriculture. A sustainable food production ? Feeding

  9. Search Engine-Crawler Symbiosis: Adapting to Community Interests

    E-print Network

    Bradshaw, Shannon

    Search Engine-Crawler Symbiosis: Adapting to Community Interests Gautam Pant, Shannon Bradshaw the crawler to better its performance. We show that the symbiosis can help the system learn about a community

  10. Bacterial symbiosis in Loripes lucinalis (Mollusca: Bivalvia)with comments

    E-print Network

    Boyer, Edmond

    Bacterial symbiosis in Loripes lucinalis (Mollusca: Bivalvia)with comments on reproductive strategy relationships, there are still many unanswered questions. Does the host bene¢t from the symbiosis via direct

  11. Dissection of Symbiosis and Organ Development by Integrated Transcriptome Analysis of Lotus japonicus

    E-print Network

    Schierup, Mikkel Heide

    Dissection of Symbiosis and Organ Development by Integrated Transcriptome Analysis of Lotus present an integrated genome-wide analysis of transcriptome landscapes in Lotus japonicus wild determinate Lotus root nodules, and eight mutants impaired at different stages of the symbiotic interaction

  12. Robotic room: Symbiosis with human through behavior media

    Microsoft Academic Search

    Tomomasa Sato; Yoshifumi Nishida; Hiroshi Mizoguchi

    1996-01-01

    This paper discusses difference between conventional industrial robotics and human symbiosis robotics considering human characteristics. It clarifies necessary robotic functions in the human symbiosis robots. The functions are: (1) sharing mental activities, (2) sharing behavior, and (3) sharing physiological activities between the human and the robot. As a typical example of a human robot symbiosis system, the authors propose a

  13. REGULAR ARTICLE Testing the ecological stability of ectomycorrhizal symbiosis

    E-print Network

    Silver, Whendee

    REGULAR ARTICLE Testing the ecological stability of ectomycorrhizal symbiosis: effects of heat, ash symbiosis, elevated nutrient levels may make the carbon cost to plants of supporting mycorrhizal fungi-fire nutrient enrichment on the ectomy- corrhizal symbiosis between Rhizopogon occidentalis and Pinus muricata

  14. ORIGINAL PAPER Onset of symbiosis and distribution patterns of symbiotic

    E-print Network

    ORIGINAL PAPER Onset of symbiosis and distribution patterns of symbiotic dinoflagellates Springer-Verlag 2009 Abstract The establishment of symbiosis in early developmental stages is important and detailed process of the onset of symbiosis. We examined larval uptake of symbiotic dino- flagellates

  15. Probabilistic Modeling for Job Symbiosis Scheduling on SMT Processors

    E-print Network

    Eeckhout, Lieven

    7 Probabilistic Modeling for Job Symbiosis Scheduling on SMT Processors STIJN EYERMAN and LIEVEN system-level priorities/shares. This article proposes probabilistic job symbiosis modeling, which predicts whether jobs will create positive or negative symbiosis when coscheduled without requiring

  16. The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

    E-print Network

    Bruns, Tom

    LETTERS The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis F. Martin1 , A and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report involved in rhizosphere colonization and symbiosis. This 65-megabase gen- ome assembly contains 20

  17. Biology of Symbiosis (BIOL 256), Fall 2005 Instructor: David Hibbett

    E-print Network

    Hibbett, David S.

    Biology of Symbiosis (BIOL 256), Fall 2005 SYLLABUS Instructor: David Hibbett Contact: e: Surindar Paracer and Vernon Ahmadjian. 2000. Symbiosis, An Introduction to Biological Associations. Second the land and establish terrestrial ecosystems. Symbiosis is a major source of evolutionary and ecological

  18. Evolutionary transitions in bacterial symbiosis Joel L. Sachs1

    E-print Network

    Sachs, Joel

    Evolutionary transitions in bacterial symbiosis Joel L. Sachs1 , Ryan G. Skophammer, and John U mutualism. Each of these transitions has occurred many times in the history of bacterial­eukaryote symbiosis evolutionary transitions in bacterial symbiosis and test hypotheses about the selective, ecological

  19. Systematic Method for Determining Intravenous Drug Treatment Strategies Aiding the Humoral Immune Response1

    E-print Network

    Balakrishnan, Venkataramanan "Ragu"

    and antibody interaction. This model is developed from relevant physiology, past predator-prey-type modeling of Veterinary Medicine Purdue University, West Lafayette, IN 47906 Keywords: predator-prey modeling, nonlinear. The method derives from a nonlinear, distributed predator -prey model that captures the dominant antigen

  20. DISCRETE AND CONTINUOUS doi:10.3934/dcdsb.2009.11.893 DYNAMICAL SYSTEMS SERIES B

    E-print Network

    Hsu, Sze-Bi

    is small. 1. Introduction. For a class of conventional predator-prey interaction models, it is known 4, June 2009 pp. 893­911 RELAXATION OSCILLATION PROFILE OF LIMIT CYCLE IN PREDATOR-PREY SYSTEM Sze. It is known that some predator-prey system can possess a unique limit cycle which is globally asymptotically

  1. Digital Object Identifier (DOI): 10.1007/s00285-002-0171-9

    E-print Network

    Ruan, Shigui

    based on a predator-prey interaction model: ut = d1uxx + Au(1 - u K ) - B uw 1+Eu , wt = d2wxx - Cw + D predator-prey model Received: 25 May 2001 / Revised version: 5 August 2002 / Published online: 19 November and small amplitude trav- eling wave train solutions for a reaction-diffusion system based on a predator-prey

  2. Systematic Method for Determining Intravenous Drug Treatment Strategies Aiding the Humoral Immune Response 1

    E-print Network

    Balakrishnan, Venkataramanan "Ragu"

    and antibody interaction. This model is developed from relevant physiology, past predator­prey­type modeling of Veterinary Medicine Purdue University, West Lafayette, IN 47906 Keywords: predator­prey modeling, nonlinear. The method derives from a nonlinear, distributed predator­prey model that captures the dominant antigen

  3. AQUATIC BIOLOGY Vol. 13: 175191, 2011

    E-print Network

    by predators. This predator­prey interaction is mediated by 3 distinct phases: genera- tion of the chemical INTRODUCTION The predator­prey relationships between bivalve clams Mercenaria mercenaria and predators, the results indicated that blue crabs dominate the predator­prey system because of the dependence on clam size

  4. The symbiont side of symbiosis: do microbes really benefit?

    PubMed Central

    Garcia, Justine R.; Gerardo, Nicole M.

    2014-01-01

    Microbial associations are integral to all eukaryotes. Mutualism, the interaction of two species for the benefit of both, is an important aspect of microbial associations, with evidence that multicellular organisms in particular benefit from microbes. However, the microbe’s perspective has largely been ignored, and it is unknown whether most microbial symbionts benefit from their associations with hosts. It has been presumed that microbial symbionts receive host-derived nutrients or a competition-free environment with reduced predation, but there have been few empirical tests, or even critical assessments, of these assumptions. We evaluate these hypotheses based on available evidence, which indicate reduced competition and predation are not universal benefits for symbionts. Some symbionts do receive nutrients from their host, but this has not always been linked to a corresponding increase in symbiont fitness. We recommend experiments to test symbiont fitness using current experimental systems of symbiosis and detail considerations for other systems. Incorporating symbiont fitness into symbiosis research will provide insight into the evolution of mutualistic interactions and cooperation in general. PMID:25309530

  5. Diminished Exoproteome of Frankia spp. in Culture and Symbiosis ? †

    PubMed Central

    Mastronunzio, J. E.; Huang, Y.; Benson, D. R.

    2009-01-01

    Frankia species are the most geographically widespread gram-positive plant symbionts, carrying out N2 fixation in root nodules of trees and woody shrubs called actinorhizal plants. Taking advantage of the sequencing of three Frankia genomes, proteomics techniques were used to investigate the population of extracellular proteins (the exoproteome) from Frankia, some of which potentially mediate host-microbe interactions. Initial two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatants indicated that cytoplasmic proteins appeared in supernatants as cells aged, likely because older hyphae lyse in this slow-growing filamentous actinomycete. Using liquid chromatography coupled to tandem mass spectrometry to identify peptides, 38 proteins were identified in the culture supernatant of Frankia sp. strain CcI3, but only three had predicted export signal peptides. In symbiotic cells, 42 signal peptide-containing proteins were detected from strain CcI3 in Casuarina cunninghamiana and Casuarina glauca root nodules, while 73 and 53 putative secreted proteins containing signal peptides were identified from Frankia strains in field-collected root nodules of Alnus incana and Elaeagnus angustifolia, respectively. Solute-binding proteins were the most commonly identified secreted proteins in symbiosis, particularly those predicted to bind branched-chain amino acids and peptides. These direct proteomics results complement a previous bioinformatics study that predicted few secreted hydrolytic enzymes in the Frankia proteome and provide direct evidence that the symbiosis succeeds partly, if not largely, because of a benign relationship. PMID:19749056

  6. Diminished exoproteome of Frankia spp. in culture and symbiosis.

    PubMed

    Mastronunzio, J E; Huang, Y; Benson, D R

    2009-11-01

    Frankia species are the most geographically widespread gram-positive plant symbionts, carrying out N(2) fixation in root nodules of trees and woody shrubs called actinorhizal plants. Taking advantage of the sequencing of three Frankia genomes, proteomics techniques were used to investigate the population of extracellular proteins (the exoproteome) from Frankia, some of which potentially mediate host-microbe interactions. Initial two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatants indicated that cytoplasmic proteins appeared in supernatants as cells aged, likely because older hyphae lyse in this slow-growing filamentous actinomycete. Using liquid chromatography coupled to tandem mass spectrometry to identify peptides, 38 proteins were identified in the culture supernatant of Frankia sp. strain CcI3, but only three had predicted export signal peptides. In symbiotic cells, 42 signal peptide-containing proteins were detected from strain CcI3 in Casuarina cunninghamiana and Casuarina glauca root nodules, while 73 and 53 putative secreted proteins containing signal peptides were identified from Frankia strains in field-collected root nodules of Alnus incana and Elaeagnus angustifolia, respectively. Solute-binding proteins were the most commonly identified secreted proteins in symbiosis, particularly those predicted to bind branched-chain amino acids and peptides. These direct proteomics results complement a previous bioinformatics study that predicted few secreted hydrolytic enzymes in the Frankia proteome and provide direct evidence that the symbiosis succeeds partly, if not largely, because of a benign relationship. PMID:19749056

  7. Getting What Is Served? Feeding Ecology Influencing Parasite-Host Interactions in Invasive Round Goby Neogobius melanostomus

    PubMed Central

    Emde, Sebastian; Kochmann, Judith; Kuhn, Thomas; Plath, Martin; Klimpel, Sven

    2014-01-01

    Freshwater ecosystems are increasingly impacted by alien invasive species which have the potential to alter various ecological interactions like predator-prey and host-parasite relationships. Here, we simultaneously examined predator-prey interactions and parasitization patterns of the highly invasive round goby (Neogobius melanostomus) in the rivers Rhine and Main in Germany. A total of 350 N. melanostomus were sampled between June and October 2011. Gut content analysis revealed a broad prey spectrum, partly reflecting temporal and local differences in prey availability. For the major food type (amphipods), species compositions were determined. Amphipod fauna consisted entirely of non-native species and was dominated by Dikerogammarus villosus in the Main and Echinogammarus trichiatus in the Rhine. However, the availability of amphipod species in the field did not reflect their relative abundance in gut contents of N. melanostomus. Only two metazoan parasites, the nematode Raphidascaris acus and the acanthocephalan Pomphorhynchus sp., were isolated from N. melanostomus in all months, whereas unionid glochidia were only detected in June and October in fish from the Main. To analyse infection pathways, we examined 17,356 amphipods and found Pomphorhynchus sp. larvae only in D. villosus in the river Rhine at a prevalence of 0.15%. Dikerogammarus villosus represented the most important amphipod prey for N. melanostomus in both rivers but parasite intensities differed between rivers, suggesting that final hosts (large predatory fishes) may influence host-parasite dynamics of N. melanostomus in its introduced range. PMID:25338158

  8. Predator-prey relationships of winter flounder, Pleuronectes americanus,

    E-print Network

    , New Jersey 07732 Abstract.- A 39-month study of the effects of cessation of sew- age sludge disposal that are variably influenced by sewage sludge. There were limited changes in winter flounder diets and abun- dance of dominant benthic macro- faunal species following cessation ofsewage sludge disposal. The com- parison

  9. Predator-prey relationships on Apiaceae at an organic farm.

    PubMed

    Shirk, Paul D; Shapiro, Jeffrey P; Reitz, Stuart R; Thomas, Jean M G; Koenig, Rosalie L; Hay-Roe, Mirian M; Buss, Lyle J

    2012-06-01

    Orius insidiosus (Say) and O. pumilio (Champion) were confirmed to be sympatric in north central Florida as the major predators of the Florida flower thrips, Frankliniella bispinosa (Morgan), on flowers of Queen Anne's lace, Daucus carota L. and false Queen Anne's lace, Ammi majus L. F. bispinosa was the predominant thrips observed on both flowers but colonized D. carota to a greater extent and earlier in the season than A. majus. Despite differences in the abundance of F. bispinosa on the two plants, neither Orius species showed host plant affinities. Population profiles for the thrips and Orius spp. followed a density dependent response of prey to predator with a large initial prey population followed by a rapid decline as the predator populations increased. The temporal increases in Orius spp. populations during the flowering season suggest that they were based on reproductive activity. As observed in a previous study, O. insidiosus had a larger population than O. pumilio and also had a predominantly male population on the flowers. By examining carcasses of the prey, there appeared to be no sexual preference of the thrips as prey by the Orius spp. as the prey pattern followed the demographics of the thrips sex ratio. Few immatures of either thrips or Orius spp. were observed on D. carota or A. majus, which suggests that oviposition and nymphal development occurred elsewhere. Based on these findings, D. carota and A. majus could serve as a banker plant system for Orius spp. PMID:22732606

  10. PERIODIC SOLUTIONS OF A PERIODIC DELAY PREDATOR-PREY SYSTEM

    Microsoft Academic Search

    LI YONGKUN

    The existence of a positive periodic solution for (dH(t) dt = r(t)H(t) h 1 H(t (t)) K(t) i (t)H(t)P(t); dP(t) dt = b(t)P(t )+ ( t ) P ( t ) H ( t ( t)) is established, where r, K, , b, are positive periodic continuous functions with period !> 0, and , are periodic continuous functions with period

  11. Cyclic Genetic Algorithm with Conditional Branching PredatorPrey Scenario

    E-print Network

    Parker, Gary B.

    Cyclic Genetic Algorithm with Conditional Branching Predator­Prey Scenario Gary Parker Computer Science Connecticut College New London, 06320 parker@conncoll.edu Parashkevov Computer Science Connecticut) found to a successful method evolving single control programs legged robots. major limitation

  12. Bifurcations and dynamics of a discrete predator–prey system

    PubMed Central

    Asheghi, Rasoul

    2014-01-01

    In this paper, we study the dynamics behaviour of a stratum of plant–herbivore which is modelled through the following F(x, y)=(f(x, y), g(x, y)) two-dimensional map with four parameters defined by where x?0, y?0, and the real parameters a, b, r, k are all positive. We will focus on the case a?b. We study the stability of fixed points and do the analysis of the period-doubling and the Neimark–Sacker bifurcations in a standard way. PMID:24963984

  13. LABORATORY #12 --BIOL 111 Predator-Prey cycles

    E-print Network

    are not present. However, this is not always a healthy situation. For example, in 1944, 29 reindeer were introduced to Saint Matthew Island in the Bering Sea. Without a predator population, the reindeer population, a population crash occurred because the reindeer denuded the area (i.e., consumed all food to the point where

  14. Nature's Partners: predators, prey & you SCIENCE IN ACTION!

    E-print Network

    Packard, Jane M.

    in the inquiry cycle relates to the others and helps us understand the science behind the myths of animal in color or hair, etc. Internal state indicators of hormonal, nutritional, age or other body condition

  15. Making the Most of Omics for Symbiosis Research

    PubMed Central

    Chaston, J.; Douglas, A.E.

    2012-01-01

    Omics, including genomics, proteomics and metabolomics, enable us to explain symbioses in terms of the underlying molecules and their interactions. The central task is to transform molecular catalogs of genes, metabolites etc. into a dynamic understanding of symbiosis function. We review four exemplars of omics studies that achieve this goal, through defined biological questions relating to metabolic integration and regulation of animal-microbial symbioses, the genetic autonomy of bacterial symbionts, and symbiotic protection of animal hosts from pathogens. As omic datasets become increasingly complex, computationally-sophisticated downstream analyses are essential to reveal interactions not evident to visual inspection of the data. We discuss two approaches, phylogenomics and transcriptional clustering, that can divide the primary output of omics studies – long lists of factors – into manageable subsets, and we describe how they have been applied to analyze large datasets and generate testable hypotheses. PMID:22983030

  16. Symbiosis, competition, and physical disturbance in the growth histories of Pliocene cheilostomebryoliths

    E-print Network

    Boyce, C. Kevin

    Symbiosis, competition, and physical disturbance in the growth histories of Pliocene cheilostomebryoliths SUSANM. KIDWELL AND ERIC D. GYLLENHAAL LETHAIA Kidwell, S.M. & Gyllenhaal,E.D. 199809 15:Symbiosis. OBryozoa, symbiosis, competition, paleoecology, taphonomy. Susan M. Kidwell [skidwell

  17. How Symbiosis Can Guide Evolution Richard A. Watson Jordan B. Pollack

    E-print Network

    Pollack, Jordan B.

    How Symbiosis Can Guide Evolution Richard A. Watson Jordan B. Pollack Dynamical and Evolutionary organisms of distinct species without direct transfer of genetic information. 1 Introduction Symbiosis relationship) are mutually beneficial. Despite being undeniably common, the phenomenon of symbiosis

  18. Microfungal “Weeds” in the Leafcutter Ant Symbiosis

    Microsoft Academic Search

    A. Rodrigues; M. Bacci Jr; U. G. Mueller; A. Ortiz; F. C. Pagnocca

    2008-01-01

    Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae)\\u000a as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage\\u000a of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens.

  19. 60 million years of co-divergence in the fig–wasp symbiosis

    Microsoft Academic Search

    Nina Rønsted; George D. Weiblen; James M. Cook; Nicolas Salamin; Carlos A. Machado; Vincent Savolainen

    2005-01-01

    Figs (Ficus; ca 750 species) and fig wasps (Agaoninae) are obligate mutualists: all figs are pollinated by agaonines that feed exclusively on figs. This extraordinary symbiosis is the most extreme example of specialization in a plant-pollinator interaction and has fuelled much speculation about co-divergence. The hypothesis that pollinator specialization led to the parallel diversification of fig and pollinator lineages (co-divergence)

  20. Transformed soybean ( Glycine max ) roots as a tool for the study of the arbuscular mycorrhizal symbiosis

    Microsoft Academic Search

    Laura Fernández; Vanesa Silvani; Josefina Bompadre; Mariana Pérgola; Alicia Godeas

    2009-01-01

    Ri T-DNA transformed roots have been used effectively in studying the interaction between various plant hosts and arbuscular\\u000a mycorrhizal (AM) fungi. We investigated the in vitro monoxenic symbiosis between the AM fungus Glomus intraradices and transformed soybean roots (TSRs). Comparisons were made between TSR system and plants of the same genotype. The extraradical\\u000a fungal structures generated in vitro culture showed

  1. The symbiosis regulator RscS controls the syp gene locus, biofilm formation and symbiotic aggregation by Vibrio fischeri

    E-print Network

    McFall-Ngai, Margaret

    The symbiosis regulator RscS controls the syp gene locus, biofilm formation and symbiotic by a microbe involves complex microbe-microbe and microbe-host interactions. Previously, we identified in Vibrio fischeri a putative sensor kinase, RscS, required for initiating symbiotic colonization of its

  2. Effects of multiple climate change factors on the tall fescue–fungal endophyte symbiosis: infection frequency and tissue chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    •Climate change (altered CO2, warming, and precipitation) may affect plant–microbial interactions, such as the Lolium arundinaceum–Neotyphodium coenophialum symbiosis, to alter future ecosystem structure and function. •To assess this possibility, tall fescue tillers were collected from an existing c...

  3. Disentangling the interaction among host resources, the immune system and pathogens.

    PubMed

    Cressler, Clayton E; Nelson, William A; Day, Troy; McCauley, Edward

    2014-03-01

    The interaction between the immune system and pathogens is often characterised as a predator-prey interaction. This characterisation ignores the fact that both require host resources to reproduce. Here, we propose novel theory that considers how these resource requirements can modify the interaction between the immune system and pathogens. We derive a series of models to describe the energetic interaction between the immune system and pathogens, from fully independent resources to direct competition for the same resource. We show that increasing within-host resource supply has qualitatively distinct effects under these different scenarios. In particular, we show the conditions for which pathogen load is expected to increase, decrease or even peak at intermediate resource supply. We survey the empirical literature and find evidence for all three patterns. These patterns are not explained by previous theory, suggesting that competition for host resources can have a strong influence on the outcome of disease. PMID:24350974

  4. Interaction strengths in balanced carbon cycles and the absence of a relation between ecosystem complexity and stability

    PubMed Central

    Neutel, Anje-Margriet; Thorne, Michael AS

    2014-01-01

    The strength of interactions is crucial to the stability of ecological networks. However, the patterns of interaction strengths in mathematical models of ecosystems have not yet been based upon independent observations of balanced material fluxes. Here we analyse two Antarctic ecosystems for which the interaction strengths are obtained: (1) directly, from independently measured material fluxes, (2) for the complete ecosystem and (3) with a close match between species and ‘trophic groups’. We analyse the role of recycling, predation and competition and find that ecosystem stability can be estimated by the strengths of the shortest positive and negative predator-prey feedbacks in the network. We show the generality of our explanation with another 21 observed food webs, comparing random-type parameterisations of interaction strengths with empirical ones. Our results show how functional relationships dominate over average-network topology. They make clear that the classic complexity-instability paradox is essentially an artificial interaction-strength result. PMID:24636521

  5. Interaction strengths in balanced carbon cycles and the absence of a relation between ecosystem complexity and stability.

    PubMed

    Neutel, Anje-Margriet; Thorne, Michael A S

    2014-06-01

    The strength of interactions is crucial to the stability of ecological networks. However, the patterns of interaction strengths in mathematical models of ecosystems have not yet been based upon independent observations of balanced material fluxes. Here we analyse two Antarctic ecosystems for which the interaction strengths are obtained: (1) directly, from independently measured material fluxes, (2) for the complete ecosystem and (3) with a close match between species and 'trophic groups'. We analyse the role of recycling, predation and competition and find that ecosystem stability can be estimated by the strengths of the shortest positive and negative predator-prey feedbacks in the network. We show the generality of our explanation with another 21 observed food webs, comparing random-type parameterisations of interaction strengths with empirical ones. Our results show how functional relationships dominate over average-network topology. They make clear that the classic complexity-instability paradox is essentially an artificial interaction-strength result. PMID:24636521

  6. Sugar for my honey: Carbohydrate partitioning in ectomycorrhizal symbiosis

    E-print Network

    Bruns, Tom

    Review Sugar for my honey: Carbohydrate partitioning in ectomycorrhizal symbiosis Uwe Nehls a, readily utilizable carbohydrates, necessary for growth and maintenance of large numbers of microbes, a symbiosis between tree roots and certain soil fungi, is a way to overcome nutrient and carbohydrate

  7. The anemonefish symbiosis: what is known and what is not

    E-print Network

    Fautin, Daphne G.

    1991-01-01

    by fish for hosts, and chance. One benefit of the symbiosis to the fish is obvious:its major source of protection is its anemone, which forms the core of its territory. The symbiosis has commonly been regarded as facultative for actinians. However...

  8. Host-microbial symbiosis in the vertebrate gastrointestinal tract and the Lactobacillus reuteri paradigm

    PubMed Central

    Walter, Jens; Britton, Robert A.; Roos, Stefan

    2011-01-01

    Vertebrates engage in symbiotic associations with vast and complex microbial communities that colonize their gastrointestinal tracts. Recent advances have provided mechanistic insight into the important contributions of the gut microbiome to vertebrate biology, but questions remain about the evolutionary processes that have shaped symbiotic interactions in the gut and the consequences that arise for both the microbes and the host. Here we discuss the biological principles that underlie microbial symbiosis in the vertebrate gut and the potential of the development of mutualism. We then review phylogenetic and experimental studies on the vertebrate symbiont Lactobacillus reuteri that have provided novel insight into the ecological and evolutionary strategy of a gut microbe and its relationship with the host. We argue that a mechanistic understanding of the microbial symbiosis in the vertebrate gut and its evolution will be important to determine how this relationship can go awry, and it may reveal possibilities by which the gut microbiome can be manipulated to support health. PMID:20615995

  9. Interrelationships between mycorrhizal symbiosis, soil pH and plant sex modify the performance of Antennaria dioica

    NASA Astrophysics Data System (ADS)

    Varga, Sandra; Kytöviita, Minna-Maarit

    2010-05-01

    AM symbiosis is usually beneficial for plants, but the benefits gained may depend on the soil abiotic factors. In dioecious plants, female and male individuals have different resource demands and allocation patterns. As a consequence of these differences, it is logical to assume that female and male plants differ in their relationship with arbuscular mycorrhizal (AM) fungi, although this has rarely been examined. We used a factorial greenhouse experiment to investigate whether female and male plants in the dioecious model species Antennaria dioica have a different relationship with their AM symbionts under two soil pH levels. In particular, we asked: (1) Do the sexes in A. dioica have sex-specific benefits from AM symbiosis? (2) If so, which sex gains the highest benefit? (3) How does soil pH affect the sex - AM fungal relationship? Our results indicate that the sexes responded similarly to AM symbiosis and pH when mycorrhizal benefit was examined as growth and phosphorus accumulation. However, the sexes differed in response to AM symbiosis in terms of survival, as mortality was increased due to AM symbiosis in female plants whilst the opposite effect was detected in males. The plant-AM fungus relationship was significantly affected by soil pH as lowering the soil pH decreased the benefits gained by the plants from the mycorrhizal fungus. Taken together, our findings indicate that AM symbiosis is beneficial for plants depending on the life history trait considered. In addition, interactions between plants and their AM symbionts are modified by soil factors and the sex of the plant.

  10. Self-Stabilizable Symbiosis for Cloud Data Center Applications: A Game Theoretic Perspective

    E-print Network

    Suzuki, Jun

    Self-Stabilizable Symbiosis for Cloud Data Center Applications: A Game Theoretic Perspective selection, emergence and symbiosis. In SymbioticSphere, each data center application consists of application (or symbiosis) between them. A symbiosis between a service and a platform is sought as a Nash

  11. Oak Root Response to Ectomycorrhizal Symbiosis Establishment: RNA-Seq Derived Transcript Identification and Expression Profiling

    PubMed Central

    Lino-Neto, Teresa; Monteiro, Filipa; Figueiredo, Andreia; Sousa, Lisete; Pais, Maria Salomé; Tavares, Rui; Paulo, Octávio S.

    2014-01-01

    Ectomycorrhizal symbiosis is essential for the life and health of trees in temperate and boreal forests where it plays a major role in nutrient cycling and in functioning of the forest ecosystem. Trees with ectomycorrhizal root tips are more tolerant to environmental stresses, such as drought, and biotic stresses such as root pathogens. Detailed information on these molecular processes is essential for the understanding of symbiotic tissue development in order to optimize the benefits of this natural phenomenon. Next generation sequencing tools allow the analysis of non model ectomycorrhizal plant-fungal interactions that can contribute to find the “symbiosis toolkits” and better define the role of each partner in the mutualistic interaction. By using 454 pyrosequencing we compared ectomycorrhizal cork oak roots with non-symbiotic roots. From the two cDNA libraries sequenced, over 2 million reads were obtained that generated 19552 cork oak root unique transcripts. A total of 2238 transcripts were found to be differentially expressed when ECM roots were compared with non-symbiotic roots. Identification of up- and down-regulated gens in ectomycorrhizal roots lead to a number of insights into the molecular mechanisms governing this important symbiosis. In cork oak roots, ectomycorrhizal colonization resulted in extensive cell wall remodelling, activation of the secretory pathway, alterations in flavonoid biosynthesis, and expression of genes involved in the recognition of fungal effectors. In addition, we identified genes with putative roles in symbiotic processes such as nutrient exchange with the fungal partner, lateral root formation or root hair decay. These findings provide a global overview of the transcriptome of an ectomycorrhizal host root, and constitute a foundation for future studies on the molecular events controlling this important symbiosis. PMID:24859293

  12. Oak root response to ectomycorrhizal symbiosis establishment: RNA-Seq derived transcript identification and expression profiling.

    PubMed

    Sebastiana, Mónica; Vieira, Bruno; Lino-Neto, Teresa; Monteiro, Filipa; Figueiredo, Andreia; Sousa, Lisete; Pais, Maria Salomé; Tavares, Rui; Paulo, Octávio S

    2014-01-01

    Ectomycorrhizal symbiosis is essential for the life and health of trees in temperate and boreal forests where it plays a major role in nutrient cycling and in functioning of the forest ecosystem. Trees with ectomycorrhizal root tips are more tolerant to environmental stresses, such as drought, and biotic stresses such as root pathogens. Detailed information on these molecular processes is essential for the understanding of symbiotic tissue development in order to optimize the benefits of this natural phenomenon. Next generation sequencing tools allow the analysis of non model ectomycorrhizal plant-fungal interactions that can contribute to find the "symbiosis toolkits" and better define the role of each partner in the mutualistic interaction. By using 454 pyrosequencing we compared ectomycorrhizal cork oak roots with non-symbiotic roots. From the two cDNA libraries sequenced, over 2 million reads were obtained that generated 19,552 cork oak root unique transcripts. A total of 2238 transcripts were found to be differentially expressed when ECM roots were compared with non-symbiotic roots. Identification of up- and down-regulated gens in ectomycorrhizal roots lead to a number of insights into the molecular mechanisms governing this important symbiosis. In cork oak roots, ectomycorrhizal colonization resulted in extensive cell wall remodelling, activation of the secretory pathway, alterations in flavonoid biosynthesis, and expression of genes involved in the recognition of fungal effectors. In addition, we identified genes with putative roles in symbiotic processes such as nutrient exchange with the fungal partner, lateral root formation or root hair decay. These findings provide a global overview of the transcriptome of an ectomycorrhizal host root, and constitute a foundation for future studies on the molecular events controlling this important symbiosis. PMID:24859293

  13. Microfungal "weeds" in the leafcutter ant symbiosis.

    PubMed

    Rodrigues, A; Bacci, M; Mueller, U G; Ortiz, A; Pagnocca, F C

    2008-11-01

    Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis. PMID:18369523

  14. The Genome of Laccaria Bi color Provides Insights into Mycorrhizal Symbiosis

    SciTech Connect

    Martin, F [UMR, France; Aerts, A. [U.S. Department of Energy, Joint Genome Institute; Ahren, D [Lund University, Sweden; Brun, A [UMR, France; Duchaussoy, F [UMR, France; Gibon, J [UMR, France; Kohler, A [UMR, France; Lindquist, E [U.S. Department of Energy, Joint Genome Institute; Pereda, V [UMR, France; Salamov, A. [U.S. Department of Energy, Joint Genome Institute; Shapiro, HJ [U.S. Department of Energy, Joint Genome Institute; Wuyts, J [UMR, France; Blaudez, D [UMR, France; Buee, M [UMR, France; Brokstein, P [U.S. Department of Energy, Joint Genome Institute; Canbeck, B [Lund University, Sweden; Cohen, D [UMR, France; Courty, PE [UMR, France; Coutinho, PM [Architecture et Fonction des Macromolecules Biologiques, UMR 6098 CNRS and Unive; Danchin, E [Architecture et Fonction des Macromolecules Biologiques, UMR 6098 CNRS and Unive; Delaruelle, C [UMR, France; Detter, J C [U.S. Department of Energy, Joint Genome Institute; Deveau, A [UMR, France; DiFazio, Stephen P [West Virginia University; Duplessis, S [UMR, France; Fraissinet-Tachet, L [Universite de Lyon, France; Lucic, E [UMR, France; Frey-Klett, P [UMR, France; Fourrey, C [UMR, France; Feussner, I [Georg-August Universitat Gottingen Germany; Gay, G [Universite de Lyon, France; Grimwood, Jane [Stanford University; Hoegger, P J [Georg-August Universitat Gottingen Germany; Jain, P [University of Alabama, Huntsville; Kilaru, S [Georg-August Universitat Gottingen Germany; Labbe, J [UMR, France; Lin, Y C [Ghent University, Belgium; Legue, V [UMR, France; Le Tacon, F [UMR, France; Marmeisse, R [Universite de Lyon, France; Melayah, D [Universite de Lyon, France; Montanini, B [UMR, France; Muratet, M [University of Alabama, Huntsville; Nehls, U [Eberhard-Karls-Universitat, Tubingen, Germany; Niculita-Hirzel, H [University of Lausanne, Switzerland; Oudot-Le Secq, M P [UMR, France; Peter, M [UMR, France; Quesneville, H [Unite de Recherches en Genomique-Info,Evry Cedex; Rajashekar, B [Lund University, Sweden; Reich, M [UMR, France; Rouhler, N [UMR, France; Schmutz, Jeremy [Stanford University; Yin, Tongming [ORNL; Chalot, M [UMR, France; Henrissat, B [Architecture et Fonction des Macromolecules Biologiques, UMR 6098 CNRS and Unive; Kues, U [Georg-August Universitat Gottingen Germany; Lucas, S [U.S. Department of Energy, Joint Genome Institute; Van de Peer, Y [Ghent University, Belgium; Podila, G [University of Alabama, Huntsville; Polle, A [Georg-August Universitat Gottingen Germany; Pukkila, P J [University of North Carolina, Chapel Hill; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Rouze, P [Ghent University, Belgium; Sanders, I R [University of Lausanne, Switzerland; Stajich, J E [University of California, Berkeley; Tunlid, A [Lund University, Sweden; Tuskan, Gerald A [ORNL; Grigoriev, I. [U.S. Department of Energy, Joint Genome Institute

    2008-01-01

    Mycorrhizal symbioses the union of roots and soil fungi are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants1,2. Boreal, temperate and montane forests all depend on ectomycorrhizae1. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are fundamental to sustainable plant productivity.

  15. Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants.

    PubMed

    Aroca, Ricardo; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; Paz, José Antonio; García-Mina, José María; Pozo, María José; López-Ráez, Juan Antonio

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress. PMID:23102876

  16. Ectomycorrhizal symbiosis enhanced the efficiency of inoculation with two Bradyrhizobium strains and Acacia holosericea growth.

    PubMed

    André, S; Galiana, A; Le Roux, C; Prin, Y; Neyra, M; Duponnois, R

    2005-07-01

    Two strains of Bradyrhizobium sp., Aust 13C and Aust 11C, were dually or singly inoculated with an ectomycorrhizal fungus, Pisolithus albus to assess the interactions between ectomycorrhizal symbiosis and the nodulation process in glasshouse conditions. Sequencing of strains Aust 13C and Aust 11C confirmed their previous placement in the genus Bradyrhizobium. After 4 months' culture, the ectomycorrhizal symbiosis promoted plant growth and the nodulation process of both Bradyrhizobium strains, singly or dually inoculated. PCR/RFLP analysis of the nodules randomly collected in each treatment with Aust 13C and/or Aust 11C: (1) showed that all the nodules exhibited the same patterns as those of the Bradyrhizobium strains, and (2) did not detect contaminant rhizobia. When both Bradyrhizobium isolates were inoculated together, but without P. albus IR100, Aust 11C was recorded in 13% of the treated nodules compared to 87% for Aust 13C, whereas Aust 11C and Aust 13C were represented in 20 and 80% of the treated nodules, respectively, in the ectomycorrhizal treatment. Therefore Aust 13C had a high competitive ability and a great persistence in soil. The presence of the fungus did not significantly influence the frequencies of each Bradyrhizobium sp. root nodules. Although the mechanisms remain unknown, these results showed that the ectomycorrhizal and biological nitrogen-fixing symbioses were very dependent on each other. From a practical point of view, the role of ectomycorrhizal symbiosis is of great importance to N2 fixation and, consequently, these kinds of symbiosis must be associated in any controlled inoculation. PMID:15616831

  17. Direct plant-predator interactions as determinants of food chain dynamics.

    PubMed

    Holt, Robert D; Barfield, Michael

    2013-12-21

    Predator-prey interactions play out in a physical matrix defined at least to some extent by the quantity and architecture of plants. Ambush predators for instance might more effectively encounter and capture prey in thick vegetation than in thin, open vegetation with good visibility. Yet these vegetation attributes are themselves potentially influenced by the intensity of herbivory, which in turn reflects the magnitude of predation. This intertwining of trophic interactions and basal biomass leads to a largely unexplored feedback in food chain dynamics. In this paper, we examine a number of extensions of standard predator-prey and food chain models that incorporate this kind of "bottom-up" influence on trophic interactions. Even simple models reveal a range of interesting behaviors. For instance, vegetation-dependent attack rates can generate alternative stable states, in one of which the predator effectively limits herbivores to low numbers, freeing plants of substantial regulation by herbivory, and in the other of which the predator is either absent, or present as an ineffective top trophic level. This can occur both in models in which the top predator is a specialist, completely dependent upon the herbivore, and in models in which the top predator is a generalist, inflicting mortality upon the focal prey species, but itself sustained in numbers by alternative prey. Another possibility is that the feedback between basal biomass and attack rates destabilizes the trophic interactions, leading to sustained oscillations in food chains. Comparable effects can arise if handling times depend upon vegetation biomass. These models illustrate the rich complexity of effects that can arise even in relatively simple community models, once one takes into account the range of potential feedback effects that are potentially present. PMID:23648188

  18. Arbuscular mycorrhizal symbiosis can mitigate the negative effects of night warming on physiological traits of Medicago truncatula L.

    PubMed

    Hu, Yajun; Wu, Songlin; Sun, Yuqing; Li, Tao; Zhang, Xin; Chen, Caiyan; Lin, Ge; Chen, Baodong

    2015-02-01

    Elevated night temperature, one of the main climate warming scenarios, can have profound effects on plant growth and metabolism. However, little attention has been paid to the potential role of mycorrhizal associations in plant responses to night warming, although it is well known that symbiotic fungi can protect host plants against various environmental stresses. In the present study, physiological traits of Medicago truncatula L. in association with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis were investigated under simulated night warming. A constant increase in night temperature of 1.53 °C significantly reduced plant shoot and root biomass, flower and seed number, leaf sugar concentration, and shoot Zn and root P concentrations. However, the AM association essentially mitigated these negative effects of night warming by improving plant growth, especially through increased root biomass, root to shoot ratio, and shoot Zn and root P concentrations. A significant interaction was observed between R. irregularis inoculation and night warming in influencing both root sucrose concentration and expression of sucrose synthase (SusS) genes, suggesting that AM symbiosis and increased night temperature jointly regulated plant sugar metabolism. Night warming stimulated AM fungal colonization but did not influence arbuscule abundance, symbiosis-related plant or fungal gene expression, or growth of extraradical mycelium, indicating little effect of night warming on the development or functioning of AM symbiosis. These findings highlight the importance of mycorrhizal symbiosis in assisting plant resilience to climate warming. PMID:25033924

  19. Permanence of a general discrete-time two-species-interaction model with non-monotonic per capita growth rates

    E-print Network

    Kang, Yun

    2011-01-01

    Combined with all density-dependent factors, the per capita growth rate of a species may be non-monotonic. One important consequence is that species may suffer from weak Allee effects or strong Allee effects. In this paper, we study the permanence of a discrete-time two-species-interaction model with non-monotonic per capita growth rates for the first time. By using the average Lyapunov functions and extending the ecological concept of the relative nonlinearity, we find a simple sufficient condition for guaranteeing the permanence of systems that can model complicated two-species interactions. The extended relative nonlinearity allows us to fully characterize the effects of nonlinearities in the per capita growth functions with non-monotonicity. These results are illustrated with specific two species competition and predator-prey models of generic forms with non-monotone per capita growth rates.

  20. Industrial Symbiosis and the Greening of the Industry in the UK: The Case of the National Industrial Symbiosis Programme 

    E-print Network

    Albertini, Vivian

    2011-08-23

    Industrial Symbiosis is part of the emerging field of Industrial Ecology, a discipline that looks at natural ecosystems as models for the development of new industrial systems. As part of the recent efforts towards environmental sustainability, many...

  1. Different soil moisture conditions change the outcome of the ectomycorrhizal symbiosis between Rhizopogon species and Pinus muricata

    Microsoft Academic Search

    Peter G. Kennedy; Kabir G. Peay

    2007-01-01

    The outcome of species interactions often depends on the environmental conditions under which they occur. In this study, we\\u000a tested how different soil moisture conditions affected the outcome of the ectomycorrhizal symbiosis between three Rhizopogon species and Pinus muricata in a factorial growth chamber experiment. We found that when grown in 7% soil moisture conditions, ectomycorrhizal plants\\u000a had similar biomass,

  2. Tree-mycorrhiza symbiosis accelerate mineral weathering: Evidences from nanometer-scale elemental fluxes

    E-print Network

    Benning, Liane G.

    Tree-mycorrhiza symbiosis accelerate mineral weathering: Evidences from nanometer-scale elemental in revised form 29 August 2011 Abstract In soils, mycorrhiza (microscopic fungal hypha) living in symbiosis

  3. Academia–Industry Symbiosis in Organic Chemistry

    PubMed Central

    2015-01-01

    Conspectus Collaboration between academia and industry is a growing phenomenon within the chemistry community. These sectors have long held strong ties since academia traditionally trains the future scientists of the corporate world, but the recent drastic decrease of public funding is motivating the academic world to seek more private grants. This concept of industrial “sponsoring” is not new, and in the past, some companies granted substantial amounts of money per annum to various academic institutions in exchange for prime access to all their scientific discoveries and inventions. However, academic and industrial interests were not always aligned, and therefore the investment has become increasingly difficult to justify from industry’s point of view. With fluctuating macroeconomic factors, this type of unrestricted grant has become more rare and has been largely replaced by smaller and more focused partnerships. In our view, forging a partnership with industry can be a golden opportunity for both parties and can represent a true symbiosis. This type of project-specific collaboration is engendered by industry’s desire to access very specific academic expertise that is required for the development of new technologies at the forefront of science. Since financial pressures do not allow companies to spend the time to acquire this expertise and even less to explore fundamental research, partnering with an academic laboratory whose research is related to the problem gives them a viable alternative. From an academic standpoint, it represents the perfect occasion to apply “pure science” research concepts to solve problems that benefit humanity. Moreover, it offers a unique opportunity for students to face challenges from the “real world” at an early stage of their career. Although not every problem in industry can be solved by research developments in academia, we argue that there is significant scientific overlap between these two seemingly disparate groups, thereby presenting an opportunity for a symbiosis. This type of partnership is challenging but can be a win–win situation if both parties agree on some general guidelines, including clearly defined goals and deliverables, biweekly meetings to track research progress, and quarterly or annual meetings to recognize overarching, common objectives. This Account summarizes our personal experience concerning collaborations with various industrial groups and the way it impacted the research programs for both sides in a symbiotic fashion. PMID:25702529

  4. Conservation and divergence of signalling pathways between roots and soil microbes – the Rhizobium -legume symbiosis compared to the development of lateral roots, mycorrhizal interactions and nematode-induced galls

    Microsoft Academic Search

    Ulrike Mathesius

    2003-01-01

    This review compares endophytic symbiotic and pathogenic root–microbe interactions and examines how the development of root structures elicited by various micro-organisms could have evolved by recruitment of existing plant developmental pathways. Plants are exposed to a multitude of soil micro-organisms which affect root development and performance. Their interactions can be of symbiotic and pathogenic nature, both of which can result

  5. Symbiosis Fall 2005 Sponsor: Erik V. Thuesen, x6584, Lab I 3065, thuesene@evergreen.edu

    E-print Network

    Thuesen, Erik V.

    1 Symbiosis Fall 2005 Sponsor: Erik V. Thuesen, x6584, Lab I 3065, thuesene@evergreen.edu Lab Aide) Presentations (D3109) 13:00-15:00 Workshop (CAL) Text books Symbiosis: an introduction to biological) Dunlap. P. V. & M. McFall-Ngai (1987). Initiation and control of the bioluminescent symbiosis between

  6. FeatureC++: On the Symbiosis of Feature-Oriented and Aspect-Oriented

    E-print Network

    Apel, Sven

    FeatureC++: On the Symbiosis of Feature-Oriented and Aspect-Oriented Programming Sven Apel, Thomas of this article are our investigations in the symbiosis of FOP and AOP. Our aim is to combine the strengths #12;to do this symbiosis (as we will explain): Multi Mixins, Aspectual Mixin Layers, and Aspectual

  7. Range Expansion Drives Dispersal Evolution In An Equatorial Three-Species Symbiosis

    E-print Network

    Paris-Sud XI, Université de

    Range Expansion Drives Dispersal Evolution In An Equatorial Three-Species Symbiosis Guillaume Le-species symbiosis endemic to coastal equatorial rainforests in Cameroon, where the impact of range dynamics species, there was no evidence of destabilization of the symbiosis at the colonization front. To our

  8. Proteomic and transcriptional analyses of coral larvae newly engaged in symbiosis with dinoflagellates

    E-print Network

    Proteomic and transcriptional analyses of coral larvae newly engaged in symbiosis, such as stony corals, engage in intracellular symbiosis with dinoflagellates, forming the trophic and structural and the transcriptome of larvae of the Hawaiian solitary coral Fungia scutaria during the onset of symbiosis

  9. Roles of Bacterial Regulators in the Symbiosis between Vibrio fischeri and Euprymna scolopes

    E-print Network

    McFall-Ngai, Margaret

    Roles of Bacterial Regulators in the Symbiosis between Vibrio fischeri and Euprymna scolopes 1 Introduction In a symbiosis, two or more evolutionarily distinct organisms communicate with one another in order to co-exist and co-adapt in their shared environment. The mutualistic symbiosis between

  10. Multiple factors contribute to keeping levels of the symbiosis regulator RscS low

    E-print Network

    McFall-Ngai, Margaret

    Multiple factors contribute to keeping levels of the symbiosis regulator RscS low Kati Geszvain Abstract Increased activity alleles (rscS1 and rscS2) of the symbiosis regulator RscS induced both syp host. Keywords Sensor kinase; histidine kinase; RscS; polysaccharide; symbiosis Introduction Two

  11. Symbiosis Winter 2004 Sponsor: Erik V. Thuesen, x6584, Lab I 3065, thuesene@evergreen.edu

    E-print Network

    Thuesen, Erik V.

    1 Symbiosis Winter 2004 Sponsor: Erik V. Thuesen, x6584, Lab I 3065, thuesene@evergreen.edu Lab books Symbiosis: an introduction to biological associations by Surindar Paracer and Vernon Ahmadjian of the bioluminescent symbiosis between Photobacterium leiognathi and leiognathid fish. Annals of the N.Y. Acad

  12. How Symbiosis Can Guide Evolution Richard A. Watson Jordan B. Pollack

    E-print Network

    Pollack, Jordan B.

    How Symbiosis Can Guide Evolution Richard A. Watson Jordan B. Pollack Dynamical and Evolutionary information. 1 Introduction Symbiosis, in its general definition, is simply the living together of different, the phenomenon of symbiosis, and especially mutualism, has for the most part been treated as a curio; a transient

  13. Lets talk about symbiosis! 9:15 Stefanie Wienkoop, Department of Ecogenomics and Systems Biology

    E-print Network

    Let´s talk about symbiosis! 9:15 Stefanie Wienkoop, Department of Ecogenomics and Systems Biology symbiosis 13:00 ­ 14:30 lunch break Session 3 14:30 Lena König, Department of Microbiology and Ecosystem symbiosis and their role to control of soil-borne fungi 16:00 Reinhard Turetschek, Department of Ecogenomics

  14. Musica ex Machina: Composing 16th-Century Counter-point with Genetic Programming and Symbiosis

    E-print Network

    Fernandez, Thomas

    1 Musica ex Machina: Composing 16th-Century Counter- point with Genetic Programming and Symbiosis a symbiosis-inspired genetic programming paradigm in which distinct agents collaborate to produce 16th introduces our current software program, GPmuse, and focuses on both the implementation of a symbiosis

  15. Shared Skeletal Support in a Coral-Hydroid Symbiosis

    PubMed Central

    Pantos, Olga; Hoegh-Guldberg, Ove

    2011-01-01

    Hydroids form symbiotic relationships with a range of invertebrate hosts. Where they live with colonial invertebrates such as corals or bryozoans the hydroids may benefit from the physical support and protection of their host's hard exoskeleton, but how they interact with them is unknown. Electron microscopy was used to investigate the physical interactions between the colonial hydroid Zanclea margaritae and its reef-building coral host Acropora muricata. The hydroid tissues extend below the coral tissue surface sitting in direct contact with the host's skeleton. Although this arrangement provides the hydroid with protective support, it also presents problems of potential interference with the coral's growth processes and exposes the hydroid to overgrowth and smothering. Desmocytes located within the epidermal layer of the hydroid's perisarc-free hydrorhizae fasten it to the coral skeleton. The large apical surface area of the desmocyte and high bifurcation of the distal end within the mesoglea, as well as the clustering of desmocytes suggests that a very strong attachment between the hydroid and the coral skeleton. This is the first study to provide a detailed description of how symbiotic hydroids attach to their host's skeleton, utilising it for physical support. Results suggest that the loss of perisarc, a characteristic commonly associated with symbiosis, allows the hydroid to utilise desmocytes for attachment. The use of these anchoring structures provides a dynamic method of attachment, facilitating detachment from the coral skeleton during extension, thereby avoiding overgrowth and smothering enabling the hydroid to remain within the host colony for prolonged periods of time. PMID:21695083

  16. Genomic analysis reveals key aspects of prokaryotic symbiosis in the phototrophic consortium “Chlorochromatium aggregatum”

    PubMed Central

    2013-01-01

    Background ‘Chlorochromatium aggregatum’ is a phototrophic consortium, a symbiosis that may represent the highest degree of mutual interdependence between two unrelated bacteria not associated with a eukaryotic host. ‘Chlorochromatium aggregatum’ is a motile, barrel-shaped aggregate formed from a single cell of ‘Candidatus Symbiobacter mobilis”, a polarly flagellated, non-pigmented, heterotrophic bacterium, which is surrounded by approximately 15 epibiont cells of Chlorobium chlorochromatii, a non-motile photolithoautotrophic green sulfur bacterium. Results We analyzed the complete genome sequences of both organisms to understand the basis for this symbiosis. Chl. chlorochromatii has acquired relatively few symbiosis-specific genes; most acquired genes are predicted to modify the cell wall or function in cell-cell adhesion. In striking contrast, ‘Ca. S. mobilis’ appears to have undergone massive gene loss, is probably no longer capable of independent growth, and thus may only reproduce when consortia divide. A detailed model for the energetic and metabolic bases of the dependency of ‘Ca. S. mobilis’ on Chl. chlorochromatii is described. Conclusions Genomic analyses suggest that three types of interactions lead to a highly sophisticated relationship between these two organisms. Firstly, extensive metabolic exchange, involving carbon, nitrogen, and sulfur sources as well as vitamins, occurs from the epibiont to the central bacterium. Secondly, ‘Ca. S. mobilis’ can sense and move towards light and sulfide, resources that only directly benefit the epibiont. Thirdly, electron cycling mechanisms, particularly those mediated by quinones and potentially involving shared protonmotive force, could provide an important basis for energy exchange in this and other symbiotic relationships. PMID:24267588

  17. SPECIAL FEATURE When Predators Don't Eat Their Prey

    E-print Network

    Bolnick, Daniel I.

    of nonconsumptive interactions between predators and their prey and illustrate that NCE may extend a predator and colleagues that reviews the role of NCE in several ``textbook'' examples of predator­prey interactions rather than decreasing prey density). The classic predator­prey interaction between wolves and moose

  18. Aeschynomene evenia, a model plant for studying the molecular genetics of the nod-independent rhizobium-legume symbiosis.

    PubMed

    Arrighi, Jean-François; Cartieaux, Fabienne; Brown, Spencer C; Rodier-Goud, Marguerite; Boursot, Marc; Fardoux, Joel; Patrel, Delphine; Gully, Djamel; Fabre, Sandrine; Chaintreuil, Clémence; Giraud, Eric

    2012-07-01

    Research on the nitrogen-fixing symbiosis has been focused, thus far, on two model legumes, Medicago truncatula and Lotus japonicus, which use a sophisticated infection process involving infection thread formation. However, in 25% of the legumes, the bacterial entry occurs more simply in an intercellular fashion. Among them, some Aeschynomene spp. are nodulated by photosynthetic Bradyrhizobium spp. that do not produce Nod factors. This interaction is believed to represent a living testimony of the ancestral state of the rhizobium-legume symbiosis. To decipher the mechanisms of this Nod-independent process, we propose Aeschynomene evenia as a model legume because it presents all the characteristics required for genetic and molecular analysis. It is a short-perennial and autogamous species, with a diploid and relatively small genome (2n=20; 460 Mb/1C). A. evenia 'IRFL6945' is nodulated by the well-characterized photosynthetic Bradyrhizobium sp. strain ORS278 and is efficiently transformed by Agrobacterium rhizogenes. Aeschynomene evenia is genetically homozygous but polymorphic accessions were found. A manual hybridization procedure has been set up, allowing directed crosses. Therefore, it should be relatively straightforward to unravel the molecular determinants of the Nod-independent process in A. evenia. This should shed new light on the evolution of rhizobium-legume symbiosis and could have important agronomic implications. PMID:22475377

  19. Evolutionary innovation: a bone-eating marine symbiosis

    Microsoft Academic Search

    Shana K. Goffredi; Victoria J. Orphan; Greg W. Rouse; Linda Jahnke; Tsegeria Embaye; Kendra Turk; Ray Lee; Robert C. Vrijenhoek

    2005-01-01

    Summary Symbiotic associations between microbes and inver- tebrates have resulted in some of the most unusual physiological and morphological adaptations that have evolved in the animal world. We document a new symbiosis between marine polychaetes of the genus Osedax and members of the bacterial group Oceano- spirillales, known for heterotrophic degradation of complex organic compounds. These organisms were discovered living

  20. Ectomycorrhizal symbiosis affects functional diversity of rhizosphere fluorescent pseudomonads

    Microsoft Academic Search

    Pascale Frey-Klett; Michaël Chavatte; Marie-Lise Clausse; Sébastien Courrier; Christine Le Roux; Jos Raaijmakers; Maria Giovanna Martinotti; Jean-Claude Pierrat; Jean Garbaye

    2004-01-01

    Summary • Here we characterized the effect of the ectomycorrhizal symbiosis on the genotypic and functional diversity of soil Pseudomonas fluorescens populations and analysed its possible consequences in terms of plant nutrition, development and health. • Sixty strains of P. fluorescens were isolated from the bulk soil of a forest nursery, the ectomycorrhizosphere and the ectomycorrhizas of the Douglas fir

  1. Estimating the age of the polydnavirus braconid wasp symbiosis

    E-print Network

    Whitfield, James B.

    Estimating the age of the polydnavirus braconid wasp symbiosis James B. Whitfield Department some braconid wasps and their cater- pillar hosts largely by suppressing or misdirecting the host immune systems. The polydnavirus­wasp relationship is an unusual appar- ent mutualism between viruses

  2. Chapter 9: Symbiosis of plants, animals, and microbes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A diversity of plants, animals and microbes on Earth abound due to evolution, climate, competition, and symbiosis. Single cell species such as microorganisms are assumed to have evolved initially. Over time, plants and animals established and flourished. As each new kingdom of life came about, the...

  3. Industrial Symbiosis: Old Wine in Recycled Bottles? Some Perspective from

    Microsoft Academic Search

    Pierre Desrochers; Samuli Leppala

    Industrial symbiosis' is a central concept in the industrial ecology literature that describes geographically proximate inter-firm relationships involving the exchange of residual materials, water and energy. Despite its obvious relevance to regional science, economic geography and urban economics, the issue is only beginning to be addressed in these sub-disciplines. This situation is paradoxical as both recovery linkages and the very

  4. Methanotrophic marine molluscan (Bivalvia, Mytilidae) symbiosis: mussels fueled by gas

    Microsoft Academic Search

    J. J. Childress; C. R. Fisher; J. M. Brooks; M. C. II Kennicutt; R. Bidigare; A. E. Anderson

    1986-01-01

    An undescribed mussel (family Mytilidae), which lives in the vicinity of hydrocarbon seeps in the Gulf of Mexico, consumes methane (the principal component of natural gas) at a high rate. The methane consumption is limited to the gills of these animals and is apparently due to the abundant intracellular bacteria found there. This demonstrates a methane-based symbiosis between an animal

  5. A study of evolutionary multiagent models based on symbiosis

    Microsoft Academic Search

    Toru Eguchi; Kotaro Hirasawa; Jinglu Hu; Nathan Ota

    2006-01-01

    Multiagent Systems with Symbiotic Learning and Evolution (Masbiole) has been proposed and studied, which is a new methodology of Multiagent Systems (MAS) based on symbiosis in the ecosystem. Masbiole employs a method of symbiotic learning and evolution where agents can learn or evolve according to their symbiotic relations toward others, i.e., considering the benefits\\/losses of both itself and an opponent.

  6. A 2-component system is involved in the early stages of the Pisolithus tinctorius-Pinus greggii symbiosis.

    PubMed

    Herrera-Martínez, Aseneth; Ruiz-Medrano, Roberto; Galván-Gordillo, Santiago Valentín; Toscano Morales, Roberto; Gómez-Silva, Lidia; Valdés, María; Hinojosa-Moya, Jesús; Xoconostle-Cázares, Beatriz

    2014-01-01

    Ectomycorrhizal symbiosis results in profound morphological and physiological modifications in both plant and fungus. This in turn is the product of differential gene expression in both co-symbionts, giving rise to specialized cell types capable of performing novel functions. During the precolonization stage, chemical signals from root exudates are sensed by the ectomycorrizal fungus, and vice versa, which are in principle responsible for the observed change in the developmental symbionts program. Little is known about the molecular mechanisms involved in the signaling and recognition between ectomycorrhizal fungi and their host plants. In the present work, we characterized a novel lactone, termed pinelactone, and identified a gene encoding for a histidine kinase in Pisolithus tictorius, which function is proposed to be the perception of the aforementioned metabolites. In this study, the use of closantel, a specific inhibitor of histidine kinase phosphorylation, affected the capacity for fungal colonization in the symbiosis between Pisolithus tinctorius and Pinus greggii, indicating that a 2-component system (TCS) may operate in the early events of plant-fungus interaction. Indeed, the metabolites induced the accumulation of Pisolithus tinctorius mRNA for a putative histidine kinase (termed Pthik1). Of note, Pthik1 was able to partially complement a S. cerevisiae histidine kinase mutant, demonstrating its role in the response to the presence of the aforementioned metabolites. Our results indicate a role of a 2-component pathway in the early stages of ectomycorrhizal symbiosis before colonization. Furthermore, a novel lactone from Pinus greggii root exudates may activate a signal transduction pathway that contributes to the establishment of the ectomycorrhizal symbiosis. PMID:24704731

  7. A 2-component system is involved in the early stages of the Pisolithus tinctorius-Pinus greggii symbiosis

    PubMed Central

    Herrera-Martínez, Aseneth; Ruiz-Medrano, Roberto; Galván-Gordillo, Santiago Valentín; Toscano-Morales, Roberto; Gómez-Silva, Lidia; Valdés, María; Hinojosa-Moya, Jesús; Xoconostle-Cázares, Beatriz

    2014-01-01

    Ectomycorrhizal symbiosis results in profound morphological and physiological modifications in both plant and fungus. This in turn is the product of differential gene expression in both co-symbionts, giving rise to specialized cell types capable of performing novel functions. During the precolonization stage, chemical signals from root exudates are sensed by the ectomycorrhizal fungus, and vice versa, which are in principle responsible for the observed change in the symbionts developmental program. Little is known about the molecular mechanisms involved in the signaling and recognition between ectomycorrhizal fungi and their host plants. In the present work, we characterized a novel lactone, termed pinelactone, and identified a gene encoding for a histidine kinase in Pisolithus tictorius, the function of which is proposed to be the perception of the aforementioned metabolites. In this study, the use of closantel, a specific inhibitor of histidine kinase phosphorylation, affected the capacity for fungal colonization in the symbiosis between Pisolithus tinctorius and Pinus greggii, indicating that a 2-component system (TCS) may operate in the early events of plant-fungus interaction. Indeed, the metabolites induced the accumulation of Pisolithus tinctorius mRNA for a putative histidine kinase (termed Pthik1). Of note, Pthik1 was able to partially complement a S. cerevisiae histidine kinase mutant, demonstrating its role in the response to the presence of these metabolites. Our results indicate a role of a TCS pathway in the early stages of ectomycorrhizal symbiosis before colonization. Furthermore, a novel lactone from Pinus greggii root exudates may activate a signal transduction pathway that contributes to the establishment of the ectomycorrhizal symbiosis. PMID:24704731

  8. Food web persistence is enhanced by non-trophic interactions.

    PubMed

    Hammill, Edd; Kratina, Pavel; Vos, Matthijs; Petchey, Owen L; Anholt, Bradley R

    2015-06-01

    The strength of interspecific interactions is often proposed to affect food web stability, with weaker interactions increasing the persistence of species, and food webs as a whole. However, the mechanisms that modify interaction strengths, and their effects on food web persistence are not fully understood. Using food webs containing different combinations of predator, prey, and nonprey species, we investigated how predation risk of susceptible prey is affected by the presence of species not directly trophically linked to either predators or prey. We predicted that indirect alterations to the strength of trophic interactions translate to changes in persistence time of extinction-prone species. We assembled interaction webs of protist consumers and turbellarian predators with eight different combinations of prey, predators and nonprey species, and recorded abundances for over 130 prey generations. Persistence of predation-susceptible species was increased by the presence of nonprey. Furthermore, multiple nonprey species acted synergistically to increase prey persistence, such that persistence was greater than would be predicted from the dynamics of simpler food webs. We also found evidence suggesting increased food web complexity may weaken interspecific competition, increasing persistence of poorer competitors. Our results demonstrate that persistence times in complex food webs cannot be predicted from the dynamics of simplified systems, and that species not directly involved in consumptive interactions likely play key roles in maintaining persistence. Global species diversity is currently declining at an unprecedented rate and our findings reveal that concurrent loss of species that modify trophic interactions may have unpredictable consequences for food web stability. PMID:25656586

  9. Nitric oxide: a multifaceted regulator of the nitrogen-fixing symbiosis.

    PubMed

    Hichri, Imène; Boscari, Alexandre; Castella, Claude; Rovere, Martina; Puppo, Alain; Brouquisse, Renaud

    2015-05-01

    The specific interaction between legumes and Rhizobium-type bacteria leads to the establishment of a symbiotic relationship characterized by the formation of new differentiated organs named nodules, which provide a niche for bacterial nitrogen (N2) fixation. In the nodules, bacteria differentiate into bacteroids with the ability to fix atmospheric N2 via nitrogenase activity. As nitrogenase is strongly inhibited by oxygen, N2 fixation is made possible by the microaerophilic conditions prevailing in the nodules. Increasing evidence has shown the presence of NO during symbiosis, from early interaction steps between the plant and the bacterial partners to N2-fixing and senescence steps in mature nodules. Both the plant and the bacterial partners participate in NO synthesis. NO was found to be required for the optimal establishment of the symbiotic interaction. Transcriptomic analysis at an early stage of the symbiosis showed that NO is potentially involved in the repression of plant defence reactions, favouring the establishment of the plant-microbe interaction. In mature nodules, NO was shown to inhibit N2 fixation, but it was also demonstrated to have a regulatory role in nitrogen metabolism, to play a beneficial metabolic function for the maintenance of the energy status under hypoxic conditions, and to trigger nodule senescence. The present review provides an overview of NO sources and multifaceted effects from the early steps of the interaction to the senescence of the nodule, and presents several approaches which appear to be particularly promising in deciphering the roles of NO in N2-fixing symbioses. PMID:25732535

  10. Symbiosis between methanogenic archaea and delta-proteobacteria as the origin of eukaryotes: the syntrophic hypothesis

    PubMed

    Moreira; Lopez-Garcia

    1998-11-01

    We present a novel hypothesis for the origin of the eukaryotic cell, or eukaryogenesis, based on a metabolic symbiosis (syntrophy) between a methanogenic archaeon (methanobacterial-like) and a delta-proteobacterium (an ancestral sulfate-reducing myxobacterium). This syntrophic symbiosis was originally mediated by interspecies H2 transfer in anaerobic, possibly moderately thermophilic, environments. During eukaryogenesis, progressive cellular and genomic cointegration of both types of prokaryotic partners occurred. Initially, the establishment of permanent consortia, accompanied by extensive membrane development and close cell-cell interactions, led to a highly evolved symbiotic structure already endowed with some primitive eukaryotic features, such as a complex membrane system defining a protonuclear space (corresponding to the archaeal cytoplasm), and a protoplasmic region (derived from fusion of the surrounding bacterial cells). Simultaneously, bacterial-to-archaeal preferential gene transfer and eventual replacement took place. Bacterial genome extinction was thus accomplished by gradual transfer to the archaeal host, where genes adapted to a new genetic environment. Emerging eukaryotes would have inherited archaeal genome organization and dynamics and, consequently, most DNA-processing information systems. Conversely, primordial genes for social and developmental behavior would have been provided by the ancient myxobacterial symbiont. Metabolism would have been issued mainly from the versatile bacterial organotrophy, and progressively, methanogenesis was lost. PMID:9797402

  11. Cellular mechanisms of Cnidarian bleaching: stress causes the collapse of symbiosis.

    PubMed

    Weis, Virginia M

    2008-10-01

    Cnidarian bleaching is a breakdown in the mutualistic symbiosis between host Cnidarians, such as reef building corals, and their unicellular photosynthetic dinoflagellate symbionts. Bleaching is caused by a variety of environmental stressors, most notably elevated temperatures associated with global climate change in conjunction with high solar radiation, and it is a major contributor to coral death and reef degradation. This review examines the underlying cellular events that lead to symbiosis dysfunction and cause bleaching, emphasizing that, to date, we have only some pieces of a complex cellular jigsaw puzzle. Reactive oxygen species (ROS), generated by damage to both photosynthetic and mitochondrial membranes, is shown to play a central role in both injury to the partners and to inter-partner communication of a stress response. Evidence is presented that suggests that bleaching is a host innate immune response to a compromised symbiont, much like innate immune responses in other host-microbe interactions. Finally, the elimination or exit of the symbiont from host tissues is described through a variety of mechanisms including exocytosis, host cell detachment and host cell apoptosis. PMID:18805804

  12. R gene-controlled host specificity in the legume–rhizobia symbiosis

    PubMed Central

    Yang, Shengming; Tang, Fang; Gao, Muqiang; Krishnan, Hari B.; Zhu, Hongyan

    2010-01-01

    Leguminous plants can enter into root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. An intriguing but still poorly understood property of the symbiosis is its host specificity, which is controlled at multiple levels involving both rhizobial and host genes. It is widely believed that the host specificity is determined by specific recognition of bacterially derived Nod factors by the cognate host receptor(s). Here we describe the positional cloning of two soybean genes Rj2 and Rfg1 that restrict nodulation with specific strains of Bradyrhizobium japonicum and Sinorhizobium fredii, respectively. We show that Rj2 and Rfg1 are allelic genes encoding a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) class of plant resistance (R) proteins. The involvement of host R genes in the control of genotype-specific infection and nodulation reveals a common recognition mechanism underlying symbiotic and pathogenic host–bacteria interactions and suggests the existence of their cognate avirulence genes derived from rhizobia. This study suggests that establishment of a root nodule symbiosis requires the evasion of plant immune responses triggered by rhizobial effectors. PMID:20937853

  13. We show an artificial world where animals (humans) and animats (software agents) interact in a coevolutionary

    E-print Network

    Pollack, Jordan B.

    learning (Tesauro, 1992, Pollack et al., 1996, Pollack and Blair, 1997), predator/prey games (Reynolds­ lack, 1996, Juillé and Pollack, 1996b). We use coevolutionary programming techniques to main­ tain our

  14. Cell wall proteins of the ectomycorrhizal basidiomycete Pisolithus tinctorius: identification, function, and expression in symbiosis.

    PubMed

    Martin, F; Laurent, P; de Carvalho, D; Voiblet, C; Balestrini, R; Bonfante, P; Tagu, D

    1999-01-01

    Specific cell-cell and cell-substrate interactions direct the growth of ectomycorrhizal fungi to their host root targets. These elaborate mechanisms lead to the differentiation of distinct multihyphal structures, the mantle, and the Hartig net. In the ectomycorrhizal basidiomycete Pisolithus tinctorius, the use of two-dimensional gel electrophoresis, immunocytochemical microscopy, and RNA blot analysis has demonstrated the differential expression of cell wall proteins (CWPs), such as hydrophobins, adhesins, and mannoproteins, during symbiotic interaction. In other fungi, these CWPs have been suggested to play a role in hyphae aggregation, intracellular signaling cascades, and cytoskeletal changes. The recent cloning of the genes for several of these CWPs in P. tinctorius allows us to address their function in symbiosis. This review summarizes our knowledge of CWPs in P. tinctorius and considers parallels with other biotrophic fungi as a possible framework for future work. PMID:10441442

  15. Ecology, 82(6), 2001, pp. 15051520 2001 by the Ecological Society of America

    E-print Network

    Hanski, Ilkka

    hypothesis primarily in Fennoscandia over the past decade. Models of predator­prey interaction have been; Microtus; models of predator­prey interaction; mus- telid; population oscillation of small rodents are considered to be the key specialist predator and the key prey species in the multispecies communities

  16. [2, 14, 15, 18], which include the ability to display various imposing forms of antipreda-

    E-print Network

    Paris-Sud XI, Université de

    Original article The predator-prey interaction between blue-bearded bee eaters (Nyctyornis athertoni eater / predator-prey interaction / defence behaviour Apidologie 31 (2000) 727­736 727 © INRA predators [11, 12, 14, 19, 20]. Thousands of bees may be deployed within seconds, to pursue the invader

  17. Ecology, 86(10), 2005, pp. 27712779 2005 by the Ecological Society of America

    E-print Network

    Bolnick, Daniel I.

    COMPETITION MODIFIES THE STRENGTH OF TRAIT- MEDIATED PREDATOR­PREY INTERACTIONS: A META-ANALYSIS DANIEL I impact of predation risk on prey is known as a ``trait- mediated interaction'' (TMI) because it results effects of predation risk. When threatened by predators, prey adopt defensive tactics whose costs can lead

  18. Functional response and prey defence level in an experimental predatorprey system

    E-print Network

    Altwegg, Res

    interaction, random effects. INTRODUCTION Prey express inducible defences only if they perceive predation risk, the paradox of enrichment predicts that predator­prey interactions become less stable with increasing nutrientFunctional response and prey defence level in an experimental predator­prey system Res Altwegg

  19. Lab 4 Questions 1. Does a larger prey popn growth rate (R ) increase or decrease the stability of the predator-

    E-print Network

    Gervais, Jennifer

    the stability of the predator- prey interaction? 2. What happens if the predators starve more quickly? Less slowly farther out. 6. What is the ultimate outcome of the predator-prey interaction, regardless quickly? 3. What happens if the predator is more efficient at converting prey into offspring? Less

  20. vol. 152, no. 4 the american naturalist october 1998 Antagonistic Coevolution over Productivity Gradients

    E-print Network

    Hochberg, Michael

    model for a 1981). Less well established than population abundance, predator-prey interaction maximal in predator-prey interactions, the predator may be most in- the patches of highest prey in prey productivity and migration act to determine impact of predators and competitors: Oksanen et al

  1. A tale of two phylogenies: comparative analyses of ecological interactions.

    PubMed

    Hadfield, Jarrod D; Krasnov, Boris R; Poulin, Robert; Nakagawa, Shinichi

    2014-02-01

    The evolution of traits involved in ecological interactions such as predator-prey, host-parasite, and plant-pollinator interactions, are likely to be shaped by the phylogenetic history of both parties. We develop generalized linear mixed-effects models (GLMM) that estimate the effect of both parties' phylogenetic history on trait evolution, both in isolation but also in terms of how the two histories interact. Using data on the incidence and abundance of 206 flea species on 121 mammal species, we illustrate our method and compare it to previously used methods for detecting host-parasite coevolution. At large spatial scales we find that the phylogenetic interaction effect was substantial, indicating that related parasite species were more likely to be found on related host species. At smaller spatial scales, and when sampling effort was not controlled for, phylogenetic effects on the number and types of parasite species harbored by hosts were found to dominate. We go on to show that in situations where these additional phylogenetic effects exist, then previous methods have very high Type I error rates when testing for the phylogenetic interaction. Our GLMM method represents a robust and reliable approach to quantify the phylogenetic effects of traits determined by, or defined by, ecological interactions and has the advantage that it can easily be extended and interpreted in a broader context than existing permutation tests. PMID:24464193

  2. Range Expansion Drives Dispersal Evolution In An Equatorial Three-Species Symbiosis

    PubMed Central

    Guillot, Sylvain; Gaume, Laurence; McKey, Doyle; Kjellberg, Finn

    2009-01-01

    Background Recurrent climatic oscillations have produced dramatic changes in species distributions. This process has been proposed to be a major evolutionary force, shaping many life history traits of species, and to govern global patterns of biodiversity at different scales. During range expansions selection may favor the evolution of higher dispersal, and symbiotic interactions may be affected. It has been argued that a weakness of climate fluctuation-driven range dynamics at equatorial latitudes has facilitated the persistence there of more specialized species and interactions. However, how much the biology and ecology of species is changed by range dynamics has seldom been investigated, particularly in equatorial regions. Methodology/Principal Findings We studied a three-species symbiosis endemic to coastal equatorial rainforests in Cameroon, where the impact of range dynamics is supposed to be limited, comprised of two species-specific obligate mutualists –an ant-plant and its protective ant– and a species-specific ant parasite of this mutualism. We combined analyses of within-species genetic diversity and of phenotypic variation in a transect at the southern range limit of this ant-plant system. All three species present congruent genetic signatures of recent gradual southward expansion, a result compatible with available regional paleoclimatic data. As predicted, this expansion has been accompanied by the evolution of more dispersive traits in the two ant species. In contrast, we detected no evidence of change in lifetime reproductive strategy in the tree, nor in its investment in food resources provided to its symbiotic ants. Conclusions/Significance Despite the decreasing investment in protective workers and the increasing investment in dispersing females by both the mutualistic and the parasitic ant species, there was no evidence of destabilization of the symbiosis at the colonization front. To our knowledge, we provide here the first evidence at equatorial latitudes that biological traits associated with dispersal are affected by the range expansion dynamics of a set of interacting species. PMID:19401769

  3. Expression Islands Clustered on the Symbiosis Island of the Mesorhizobium loti Genome

    PubMed Central

    Uchiumi, Toshiki; Ohwada, Takuji; Itakura, Manabu; Mitsui, Hisayuki; Nukui, Noriyuki; Dawadi, Pramod; Kaneko, Takakazu; Tabata, Satoshi; Yokoyama, Tadashi; Tejima, Kouhei; Saeki, Kazuhiko; Omori, Hirofumi; Hayashi, Makoto; Maekawa, Takaki; Sriprang, Rutchadaporn; Murooka, Yoshikatsu; Tajima, Shigeyuki; Simomura, Kenshiro; Nomura, Mika; Suzuki, Akihiro; Shimoda, Yoshikazu; Sioya, Kouki; Abe, Mikiko; Minamisawa, Kiwamu

    2004-01-01

    Rhizobia are symbiotic nitrogen-fixing soil bacteria that are associated with host legumes. The establishment of rhizobial symbiosis requires signal exchanges between partners in microaerobic environments that result in mutualism for the two partners. We developed a macroarray for Mesorhizobium loti MAFF303099, a microsymbiont of the model legume Lotus japonicus, and monitored the transcriptional dynamics of the bacterium during symbiosis, microaerobiosis, and starvation. Global transcriptional profiling demonstrated that the clusters of genes within the symbiosis island (611 kb), a transmissible region distinct from other chromosomal regions, are collectively expressed during symbiosis, whereas genes outside the island are downregulated. This finding implies that the huge symbiosis island functions as clustered expression islands to support symbiotic nitrogen fixation. Interestingly, most transposase genes on the symbiosis island were highly upregulated in bacteroids, as were nif, fix, fdx, and rpoN. The genome region containing the fixNOPQ genes outside the symbiosis island was markedly upregulated as another expression island under both microaerobic and symbiotic conditions. The symbiosis profiling data suggested that there was activation of amino acid metabolism, as well as nif-fix gene expression. In contrast, genes for cell wall synthesis, cell division, DNA replication, and flagella were strongly repressed in differentiated bacteroids. A highly upregulated gene in bacteroids, mlr5932 (encoding 1-aminocyclopropane-1-carboxylate deaminase), was disrupted and was confirmed to be involved in nodulation enhancement, indicating that disruption of highly expressed genes is a useful strategy for exploring novel gene functions in symbiosis. PMID:15060047

  4. A stochastic structural stability theory model of the drift wavezonal flow system

    E-print Network

    Farrell, Brian F.

    of solutions to the predator-prey model. This analogy is founded on statistical random wave theory and captures results of random wave theory, but the predator-prey model is not itself a solution of the equations spatial scale zonal jets. In this work a comprehensive theory for the interaction of jets with turbulence

  5. SIAM J. APPL. MATH. c 2007 Society for Industrial and Applied Mathematics Vol. 67, No. 5, pp. 14531464

    E-print Network

    Kuang, Yang

    . In studying the interaction between predators and their prey, it is crucial to determine what specific form­1464 HETEROCLINIC BIFURCATION IN THE MICHAELIS­MENTEN-TYPE RATIO-DEPENDENT PREDATOR-PREY SYSTEM BINGTUAN LI AND YANG- dependent predator-prey system is rigorously established. Limit cycles related to the heteroclinic

  6. August 19, 2009 14:50 WSPC -Proceedings Trim Size: 9.75in x 6.5in sherratt SPATIOTEMPORAL DYNAMICS IN ECOLOGY

    E-print Network

    Sherratt, Jonathan A.

    in cyclic predator-prey systems show plane waves behind the invasion front. When the selected plane wave Stability; complex Ginzburg-Landau equation 1. Invasions in Cyclic Predator-Prey Systems Many natural, but in some cases there is strong evidence that the underlying cause is the interaction between a predator

  7. IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS--PART B: CYBERNETICS, VOL. 37, NO. 6, DECEMBER 2007 1567 Self-Organizing Neural Architectures and

    E-print Network

    Tan, Ah-Hwee

    multiagent environment based on minefield navigation and a predator/prey pursuit tasks. Experiments of performance. For the predator/prey pursuit task, we experiment with various cooperative strategies and find (RL), as it enables an autonomous agent to learn through interaction with the environment, based

  8. doi: 10.1098/rsta.2010.0270 , 5661-56773682010Phil. Trans. R. Soc. A

    E-print Network

    de Aguiar, Marcus A. M.

    formation and outbreaks occur if the predators have a limited neighbourhood of interaction with the preys investigated the phenomenon of population outbreaks in a spatial predator­prey model, and we found that pattern strategy is crucial for existence of this optimal home range area. Keywords: predator­prey model; home

  9. Strigolactones and Their Role in Arbuscular Mycorrhizal Symbiosis

    Microsoft Academic Search

    Soizic Rochange

    \\u000a Molecular signals are exchanged between arbuscular mycorrhizal (AM) fungi and their host plants during the pre-symbiotic stage,\\u000a and help mutual recognition prior to any contact between the two partners. In particular, root exudates from host plants are\\u000a known to trigger a switch in fungal development and metabolism, committing the fungus towards the establishment of the symbiosis.\\u000a Strigolactones, a group of

  10. Establishment of Coral–Algal Symbiosis Requires Attraction and Selection

    PubMed Central

    Yamashita, Hiroshi; Suzuki, Go; Kai, Sayaka; Hayashibara, Takeshi; Koike, Kazuhiko

    2014-01-01

    Coral reef ecosystems are based on coral–zooxanthellae symbiosis. During the initiation of symbiosis, majority of corals acquire their own zooxanthellae (specifically from the dinoflagellate genus Symbiodinium) from surrounding environments. The mechanisms underlying the initial establishment of symbiosis have attracted much interest, and numerous field and laboratory experiments have been conducted to elucidate this establishment. However, it is still unclear whether the host corals selectively or randomly acquire their symbionts from surrounding environments. To address this issue, we initially compared genetic compositions of Symbiodinium within naturally settled about 2-week-old Acropora coral juveniles (recruits) and those in the adjacent seawater as the potential symbiont source. We then performed infection tests using several types of Symbiodinium culture strains and apo-symbiotic (does not have Symbiodinium cells yet) Acropora coral larvae. Our field observations indicated apparent preference toward specific Symbiodinium genotypes (A1 and D1-4) within the recruits, despite a rich abundance of other Symbiodinium in the environmental population pool. Laboratory experiments were in accordance with this field observation: Symbiodinium strains of type A1 and D1-4 showed higher infection rates for Acropora larvae than other genotype strains, even when supplied at lower cell densities. Subsequent attraction tests revealed that three Symbiodinium strains were attracted toward Acropora larvae, and within them, only A1 and D1-4 strains were acquired by the larvae. Another three strains did not intrinsically approach to the larvae. These findings suggest the initial establishment of corals–Symbiodinium symbiosis is not random, and the infection mechanism appeared to comprise two steps: initial attraction step and subsequent selective uptake by the coral. PMID:24824794

  11. Some aspects of optimal human-computer symbiosis in multisensor geospatial data fusion

    NASA Astrophysics Data System (ADS)

    Levin, E.; Sergeyev, A.

    Nowadays vast amount of the available geospatial data provides additional opportunities for the targeting accuracy increase due to possibility of geospatial data fusion. One of the most obvious operations is determining of the targets 3D shapes and geospatial positions based on overlapped 2D imagery and sensor modeling. 3D models allows for the extraction of such information about targets, which cannot be measured directly based on single non-fused imagery. Paper describes ongoing research effort at Michigan Tech attempting to combine advantages of human analysts and computer automated processing for efficient human computer symbiosis for geospatial data fusion. Specifically, capabilities provided by integration into geospatial targeting interfaces novel human-computer interaction method such as eye-tracking and EEG was explored. Paper describes research performed and results in more details.

  12. Symbiosis between microorganisms from kombucha and kefir: Potential significance to the enhancement of kombucha function.

    PubMed

    Yang, Zhiwei; Zhou, Feng; Ji, Baoping; Li, Bo; Luo, Yangchao; Yang, Li; Li, Tao

    2010-01-01

    Gluconacetobacter sp. A4 (G. sp. A4), which had strong ability to produce d-saccharic acid 1, 4 lactone (DSL), was the key functional bacteria isolated from the kombucha preserved. This paper investigated the interaction between G. sp. A4 and ten different strains of lactic acid bacteria (LAB) obtained from kefir. The result suggested that the LAB promoted DSL production of G. sp. A4 to different extents, ranging from 4.86% to 86.70%. Symbiosis between G. sp. A4 and LAB was studied. LAB's metabolites, xylitol, and acetic acid, were utilized by G. sp. A4, and it promoted the growth of G. sp. A4 and yield of DSL. Therefore, in developing starter cultures for kombucha fermentation process, a mixed flora of LAB and G. sp. A4 would be the optimal combination. PMID:18810658

  13. Quantitative assessment of urban and industrial symbiosis in Kawasaki, Japan.

    PubMed

    Van Berkel, Rene; Fujita, Tsuyoshi; Hashimoto, Shizuka; Fujii, Minoru

    2009-03-01

    Colocated firms can achieve environmental benefit and competitive advantage from exchanging physical resources (known as industrial symbiosis) with each other or with residential areas (referenced here as urban symbiosis). Past research illustrated that economic and environmental benefits appear self-evident, although detailed quantification has only been attempted of symbioses for energy and water utilities. This article provides a complimentary case studyfor Kawasaki, Japan. The 14 documented symbioses connect steel, cement, chemical, and paperfirms and their spin-off recycling businesses. Seven key material exchanges divert annually at least 565 000 tons of waste from incineration or landfill. Four of these collectively present an estimated economic opportunity of 13.3 billion JPY (approximately 130 million USD) annually. Five symbioses involve utilization of byproduct and two sharing of utilities. The others are traditional or new recycling industries that do not specifically benefit from geographic proximity. The synergistic effect of urban and industrial symbiosis is unique. The legislative framework for a recycling-oriented society has contributed to realization of the symbioses, as has the availability of government subsidies through the Eco-Town program. PMID:19350890

  14. Nitric oxide in legume–rhizobium symbiosis

    Microsoft Academic Search

    Eliane Meilhoc; Alexandre Boscari; Claude Bruand; Alain Puppo; Renaud Brouquisse

    2011-01-01

    Nitric oxide (NO) is a gaseous signaling molecule with a broad spectrum of regulatory functions in plant growth and development. NO has been found to be involved in various pathogenic or symbiotic plant–microbe interactions. During the last decade, increasing evidence of the occurrence of NO during legume–rhizobium symbioses has been reported, from early steps of plant–bacteria interaction, to the nitrogen-fixing

  15. Observations on Physiology and Symbiosis of the Large Benthic Foraminiferan Operculina Ammonoides from the Gulf of Eilat

    E-print Network

    Simon, Emmanuel

    Observations on Physiology and Symbiosis of the Large Benthic Foraminiferan Operculina Ammonoides. Their symbiosis, calcification physiology, and ecological response to environmental changes are poorly understood that calcification is increasing in fed individuals. These data suggest that the symbiosis in LBF is quite different

  16. Electronic copy available at: http://ssrn.com/abstract=2014754 Joshua M. Pearce, "Industrial Symbiosis for Very Large Scale Photovoltaic

    E-print Network

    Paris-Sud XI, Université de

    Symbiosis for Very Large Scale Photovoltaic Manufacturing", Renewable Energy 33, pp. 11011108, 2008. http://dx.doi.org/10.1016/j.renene.2007.07.002 Industrial Symbiosis of Very Large Scale Photovoltaic Manufacturing energy demands. This article explores utilizing industrial symbiosis to obtain economies of scale

  17. 3.12 Competition models, Mutualism or Symbiosis The general n -species competition model is decribed by the following systems

    E-print Network

    Hsu, Sze-Bi

    §3.12 Competition models, Mutualism or Symbiosis The general n -species competition model condition on the left (right) hand of converges to ),0( 2K ))0,(( 1K . Mutualism or Symbiosis or symbiosis often plays the crucial role in promoting and #12;even maintaining such species; plant and seed

  18. A plant receptor-like kinase required for both bacterial and fungal symbiosis

    Microsoft Academic Search

    Silke Stracke; Catherine Kistner; Satoko Yoshida; Lonneke Mulder; Shusei Sato; Takakazu Kaneko; Satoshi Tabata; Niels Sandal; Jens Stougaard; Krzysztof Szczyglowski; Martin Parniske

    2002-01-01

    Most higher plant species can enter a root symbiosis with arbuscular mycorrhizal fungi, in which plant carbon is traded for fungal phosphate. This is an ancient symbiosis, which has been detected in fossils of early land plants. In contrast, the nitrogen-fixing root nodule symbioses of plants with bacteria evolved more recently, and are phylogenetically restricted to the rosid I clade

  19. PRESENCE AND DISTRIBUTION OF FUNGAL SYMBIOSIS IN CHEILANTHES FEEI AND CHEILANTHES LANOSA IN SOUTHEASTERN

    E-print Network

    Swatzell, Lucinda

    TITLE PAGE PRESENCE AND DISTRIBUTION OF FUNGAL SYMBIOSIS IN CHEILANTHES FEEI AND CHEILANTHES LANOSA University PRESENCE AND DISTRIBUTION OF FUNGAL SYMBIOSIS IN CHEILANTHES FEEI AND CHEILANTHES LANOSA #12;ABSTRACT Cheilanthes feei (Polypodiaceae) is a xerophytic fern that grows exclusively on dry

  20. Assessing the adaptability of the actinorhizal symbiosis in the face of environmental change

    Microsoft Academic Search

    Pier-Anne Bélanger; Cyntia Bissonnette; Audrey Bernèche-D’Amours; Jean-Philippe Bellenger; Sébastien Roy

    2011-01-01

    Human activity, and in particular industrial activity, has altered natural environments. Here we present an experimental approach adapted to study the actinorhizal symbiosis in alder trees and shrubs submitted to abiotic stress. We measured the impact of exogenous nitrogen on the establishment of the alder symbiosis with Frankia sp., and its primary function; nitrogen fixation. Results showed our version of